Unit failed to boot and observe the followng; - No start-up display - No CMOS boot-up display - Hard disk clicking sound and OS won't start

First remove the hard disk and see whether you have boot error if you have boot error insert the os cd in to drive and boot from the cd if it works fine you have a problem with the hard disk to clear the hard disk problem use a desktop computer and insert the hard disk as slave in the desk top and boot the desktop with the original drive then right click my computer click mange then disk management and find the laptop hard disk the delete all the part ion in the laptop disk then switch off the desk top and insert the hard disk in the laptop and reload the OS

Typically; it's the boot sector of the hard drive that fails. That's why it asked for the OS disk. If it won't even boot now; but appears to charge OK, then you are correct in suspecting the motherboard... could be over heating. You're beyond what you can trouble shoot and it needs to be looked at by a technincian

Verify in the computer CMOS, that the first boot option is your DVD/CDROM unit. To enter the CMOS turn on your computer and press the F2 or Delete key of your keyboard. The key change depending the computer manufacturer. Normally the computer show for some seconds in the monitor the correct key to enter to the CMOS or BIOS.
When you enter to the CMOS, look for the Boot Order section and adjust it.

Sounds like you disconnecting the cmos and it helping was just coincidence.The hard drive may be bad or your OS needs to be repaired or reinstalled.Alot of times when it does as you indicated the boot sector maybe corrupt or your hard drive has bad sectors where the boot info was written on the hard disk

Yuo need a lot of try and error to be successful.
First your OS and the BOOT disk that comes with your machine.But if you dont had the CD you need to buy and download it.
Store like Bestbuy,CompUSA,etc.. sell this CD,s or go to this LINK where you can buy it online and download it, choose your OS and any other specs about your System.
After all you need to BURN the files in a blank CD or order for mail shipment.

Then we going to BOOT the system id the CD drive.

To rebuild your hard drive, do the following:

1. Power up your Acer system.
2. When prompted (after memory testing completes), press CTRL + ALT + ESC to enter CMOS setup.
3. At the CMOS Setup screen select Advanced BIOS Features
4. Verify the Boot Options Sequence is set to the following order:
   1st [CD-ROM]
   2nd [Floppy Disk]
   3rd [Hard Disk]
5. Insert the Acer System CD, DISK 1 in your CD-ROM drive.
6. Press F10 to exit and save. When prompted, Do you want to save CMOS data?, select [Yes], then press ENTER.
7. The system will reboot from the CD-ROM. After booting from the CD-ROM, you will see the Acer Hard Drive Rebuild options displayed.
   
   Note: Use your mouse for choice selections during the HDD recovery process. The mouse will respond slowly during this procedure, DO NOT press the Enter key. Pressing the Enter key will cause the HDD recovery process to terminate.
   
8. Select HDD Full Rebuild and follow the on-screen instructions.
9. When prompted to insert Acer Recovery CD, DISK 2, wait for the CD-ROM to eject DISK 1.
10. Close the CD-ROM tray and click OK. The system will continue to rebuild the hard drive back to factory load.

After being prompted to remove disk and restart system the unit will load system software and hardware. During this process the system will reboot several times.
Your Microsoft Certificate of Authenticity (COA) ID number will automatically be entered for you. Should you need this number for any reason, look for your Microsoft Certificate of Authenticity (COA) ID number on the cover of your system.

"thumbs and post back!"

A bad cmos battery will not affect startup - its role is to main settings such as clock, boot up preferences, etc. If that battery goes bad computer will still boot. Settings are lost and unit has to be reset.
Issue can be caused by corrupted cmos, bad hard drive, corrupted OS, bad memory, bad peripheral. Does the cmos post? If it does post and you see the initial gobbly g--k on screen, chances are it is good and the issue lies else where. Using other computer do diagnostics on hard drive. If it checks out ok, it may be a corrupted OS or the master boot up record of the hard drive. If memory is bad there is a usual 2 beep signal at posting time. And if you think it is the OS use the restore disks that you have for the computer. If none
you will have to get an OS disk for software that is compatible with your unit. Good luck.

Do you have the original start up disc? If so use it. If not there is generally a button to use at start up that will get you to a screen where you can restore your computer to a previous date. The button is usually F10 or F11 or one of the f keys. Also make sure that you don't have a disk in one of the drives. Take everything out and try starting it up. Good luck.

can you still go to CMOS SETUP?
how many beep and beep long of your pc while booting?
if you can still go to cmos setup try delete all partition using your windows setup then install a fresh copy of windows. if there are no partition found means theres a problem with your hardisk try put your hard disk to secondary if in primary or use different data cable might be the problem if the data cable is not the problem see the power supply of your hard disk is fine try swap the power suppply of your hard disk and cd-rom drive or extra power supply if power supply is not problem .
Buy a Brand New Harddisk might fix it your hard disk might have plenty of bad sector thats why doesn't boot anymore.
Hope i help you out ^)^

is the hard disk detectable in the cmos setup? to know how to enter the cmos setup look for the press "DEL / F2 / F10 to enter setup when you power up the pc. check for the boot option under cmos and check the hdd if cmos can detect it. otherwise hard drive has a problem. if hard drive is detectable, try reinstalling windows xp. other means is to check boot sequence by pressing F11 during start up. this will display the option on which you would like to boot from.

Hi, If your computer stops booting from the hard drive and is asking for a boot disk, then: 1. The motherboard/PC is no longer recognizing the hard disk; 1.1 Go to your CMOS/BIOS setup and manually detect the hard disk, save & exit. 2. The CMOS/BIOS is set to boot from other devices such as CD, FDD or USB but not from the HD. If after configuring the CMOS/BIOS and the hard disk is not recognized, then it is probably defective and therefore need to be replaced. If the hard disk is recognized but will not boot, then some files of your OS needed to boot are missing, corrupt or overwritten. You would need to re-install your OS and opt for a "repair". Hope this be of some help/idea. Post back how things stand or should you need additional information. good luck and kind regards.