You can restore the phone to factory default by going to Start-Settings-System-Remove Programs. Or you can do a hard reset by pressing the Comm button + Off button + Vioce cmd button + pressing reset pin on side of phone at the same time and holding it for about 20 sek. till phone restarts I did exactly the above with no results. I do not have owners manual and i do not know if it comes with preset manufacturers code

Step 1:
Which operating system ?
Laptop computers can be wonderful devices, except when the need to troubleshoot arises. Acer laptops are no different. A quick way to fix many problems with an Acer laptop running Windows is to reset it to factory settings. Resetting your Acer laptop to factory settings can eliminate slow operation, registry problems, virus problems and spyware issues. What's more, a factory reset of your laptop may reduce the need for a full reinstallation of Windows.

Back up all necessary data to an external device such as a disk, flash drive or hard drive Make sure all programs are closed and shut down your Acer laptop. Detach any external hardware such as an external hard drive or printer. Press the Power button to boot your Acer laptop. Press "Alt-F10" on your keyboard when the Acer screen appears at the start of the boot-up process. Wait a moment while Windows loads the reset files. Select "Restore System from factory default" in the Acer eRecovery Management window. Click "Next" on the next screen to continue. Click "Next" on the following destination information window. This will pop up a notice telling you that resetting your Acer laptop will erase all data and restore the laptop to its original settings and configuration. Click "OK" in the notice window to proceed with resetting your Acer laptop. Wait while your Acer laptop is reset to factory settings.

I would say that you should try a hard reset.

HTC HD2 hard reset
If a normal reset does not solve a system problem, you can perform a factory reset. After a factory reset, the phone is restored to its default settings-the way it was when you first purchased it and turned it on. You will lose any programs you installed, data you entered, and settings you customized on your phone, and only Windows Mobile software and other pre-installed programs will remain.

There are two ways to do a factory reset. One way is perform a clear storage process through the phone settings. The other way is to perform a hard reset by pressing certain buttons on your phone, in cases when you are unable to start up your phone and enter the phone settings.

Warning! Your phone will be set back to factory default settings. Make sure that any additional installed programs and important data on your phone have been backed up before you perform a factory reset.

Important If Encrypt files when placed on a storage card is enabled, back up all files from the storage card before performing a factory reset (Clear Storage or hard reset) or updating the operating system. Otherwise, you will no longer be able to access the encrypted files on the storage card. Use ActiveSync or Windows Mobile Device Center to transfer files between your storage card and computer. After the procedure, copy your files back to the storage card.

To perform a HTC HD2 Leo hard reset with buttons
1. With the phone turned off, press and hold the VOLUME UP and VOLUME DOWN buttons, then press the END/POWER button shortly and release it. You will then see this message on the screen.



2. Release the VOLUME UP and VOLUME DOWN buttons.
3. Press the VOLUME UP button to perform the hard reset, or press any other button to cancel the reset.

Hard or master reset

A hard reset restores the original factory settings and may erase all downloaded content, including ringtones, images, programs, and contacts stored in the internal memory. To perform a hard reset, follow these steps:

1. Back up all necessary data by copying any files you want to save from your phone to your computer.
2. From the Start screen, swipe left.
3. Tap Settings.
4. Tap about.
5. Tap reset your phone.
6. Tap yes.

Hard or master reset using hardware buttons

If the phone is locked, frozen, or unresponsive, you can hard reset it using the hardware keys instead of the menu. A hard reset restores the original factory settings and may erase all downloaded content, including ringtones, images, programs, and contacts stored in the internal memory. To perform a hard reset using hardware keys, follow these steps:

1. Back up all necessary data by copying any files you want to save from your phone to your computer.
2. With the phone turned off, press and hold the Volume Up and Volume Down keys.
3. While still pressing the Volume keys, quickly press the Power/Lock key.
4. When the device displays 'This operation will delete all your personal data, and reset all settings to manufacturer default. Press Vol Down to restore manufacturer default, or press other keys to cancel.', release the Volume keys.
5. Press the Volume Down key to reset the device.

A Hard Reset restores the device to its default settings - the way it was when you first purchased it and turned it on. Any programs you installed, data you entered, and settings you customized on the device will be lost. Only Windows Mobile software and other pre-installed programs will remain.
There are 2 ways to perform a Hard Reset on this device:
Menu path

1. From the Today Screen, go to Start>Settings.Select the System Tab and then tap on Clear Storage.
2. Enter in the password provided on the display of the device (should be 1234) and tap Yes.
3. The device will begin the Master Reset Process.

Keystroke Method

1. Power the device off.
2. Press and hold the left SOFT KEY and the right SOFT KEY, and at the same time, use the stylus to press the RESET button at the bottom of
   your device.
3. Release the stylus, but continue pressing the two SOFT KEY's until you see the following message on the screen:
   • This operation will delete all your personal data, and reset all settings to the manufacturer default settings. Press SEND to restore manufacturer defaults, or press any other button to cancel.
4. Release the two SOFT KEY's, and then press TALK.
   • Warning! Your device will be set back to factory default settings. Please ensure any additional installed programs and/or user data is backed up before proceeding.

Unlike other laptops, Acer laptops integrate a computer management utility called 'Acer eRecovery Management' to create backup of hard drive data, create restore point, reinstall applications & drivers, and reset Acer laptop to factory setting.

Step 1: Before starting your Acer laptop, ensure that there is no external storage device attached to it. Now start your laptop.

Step 2: Press 'Alt + F10' when the laptop starts booting, and wait for a moment while Windows loads the reset files.

Step 3: When 'Acer eRecovery Management' window appears, select 'Restore System from factory default' and click 'Next' to continue.

Step 4: Again click 'Next' to reset your Acer laptop. This process will erase all data from your hard disk and reset your Acer laptop to original factory settings.

Step 5: Click 'OK' in the notification window to begin the the resetting operation. Now wait while your Acer laptop is reset to factory settings.

Tips: You can also create a backup copy of your laptop data before factory reset. Simply click 'Backup' in 'Acer eRecovery Management' window.

If you have any other issue with your Acer laptop/desktop/Notebook, fget technical assistance at http://www.vtechsquad.com/acer-support/

I think you'll have to hard reset your device, in order to bypass its present condition.You, most probaly, know that a hard reset will restore your device to its factory defaults, thus deleting all programs you have installed, as well as your personal data and settings. In order to hard reset your device, press and hold both the comm manager and the voice memo buttons, and, whilst keeping them pressed, briefly press the reset button with the stylus pen. Release the buttons when isntructions pop up on-screen, and follow then.
Hope you are able to have a fully functional device soon.
Cheers! Carlos

If you perform a hard reset, it should allow you to choose the language the phone displays. Just be sure to back up all your info/programs you have on the phone because it will go back to factory default when you do this!!!

Performing a hard reset
If a normal reset does not solve a system problem, you can perform a hard (full) reset. After a hard reset, the device is restored to its default settings—the way it was when you first purchased it and turned it on. You will lose any programs you installed, data you entered, and settings you customized on your device, and only Windows Mobile® software and other pre-installed programs will remain.
Warning! Your device will be set back to factory default settings. Make sure that any additional installed programs and/or user data have been backed up before you perform a hard reset.
Important If Encrypt files when placed on a storage card is enabled, backup all files from the storage card before using Clear Storage, hard reset, or updating the operating system. Otherwise you will no longer be able to access the encrypted files on the storage card. Use ActiveSync or Windows Mobile Device Center to transfer files between your storage card and computer. After the procedure, copy your files back to the storage card.
To perform a hard reset
1. With the device turned off, press and hold the VOLUME UP and VOLUME DOWN buttons, then briefly press the POWER button.
2. Continue pressing the VOLUME UP and VOLUME DOWN buttons until you see this message on the screen:
This operation will delete all your personal data, and reset all settings to the manufacturer default settings. Press VolUp to restore manufacturer defaults, or press other keys to cancel.
3. Release the VOLUME UP and VOLUME DOWN buttons.
4. Press the VOLUME UP button to perform the hard reset, or press any other button to cancel the reset.
Using Clear Storage
If you can access the device settings, you can use Clear Storage to reset your device back to factory default settings.
1. Tap Start > Settings, and then tap All Settings.
2. On the System tab, tap Clear Storage.
3. Enter "1234" and then tap Yes.

you can restore the phone to factory default by going to Start-Settings-System-Remove Programs. Or you can do a hard reset by pressing the Comm button + Off button + Vioce cmd button + pressing reset pin on side of phone at the same time and holding it for about 20 sek. till phone restarts. 

Hard Reset
Press and hold the TALK and END buttons, and at the same time, use the stylus to press the RESET button at the bottom of your device.
Release the stylus, but continue pressing the TALK and END buttons until you see the following message on the screen:This operation will delete all your personal data, and reset all settings to manufacturer default. Press Action to restore manufacturer default, or press other keys to cancel.
Release the TALK and END buttons, and then press ENTER on your device.
Warning! Your device will be set back to factory default settings. Please ensure any additional installed programs and/or user data have been backed up before a hard reset is performed.

Another way of clearing the device storage and reset all setings back to factory default settings is to use the Clear Storage feature. You will lose all your data and files on the device storage when you use Clear Storage, so make sure to do a backup first.

Tap Start > Settings > System tab > Clear Storage.
Enter “1234” then tap Yes.

Occasionally, you may need to reset your device. A normal (or soft) reset of your device clears all active program memory and shuts down all active programs. This can be useful when your device is running slower than normal, or a program is not performing properly. A soft reset is also necessary after the installation of some programs. If a soft reset is performed when programs are running, unsaved work will be lost.
You can also perform a hard reset (also known as a full reset). A hard reset should be performed only if a normal reset does not solve a system problem. After a hard reset, the device is restored to its default settings — the way it was when you first purchased it and turned it on. Any programs you installed, data you entered, and settings you customized on your device will be lost. Only Windows Mobile software and other pre-installed programs will remain.
To perform a soft reset
• Use the stylus to press the RESET button found on the lower left side of your device. Your device restarts and displays the Today screen.


To perform a hard reset

1. Press and hold the Left SOFT KEY and the Right SOFT KEY, and at the same time, use the stylus to press the RESET button at the lower left side of your device.
2. Release the stylus, but continue pressing the two soft key buttons. Release them only when you see the following message on your device screen: “Press Send to restore manufacturer default, or press other keys to cancel.“
3. Press on your device. Warning! Your device will be set back to factory default settings. Please ensure any additional installed programs and/or user data have been backed up before a hard reset is performed.