Here are a few things to try:
1. Check your hard drive is installed and properly seated in its socket.
2. Try boot into Safe Mode by pressing and holding the F8 key. When you get into Advanced options select Boot into Safe mode. If it is able to boot into safe mode then it is a driver issue and I suggest you uninstall any recently installed drivers prior to the problem.
3. Press the "delete" key on you keyboard as the laptop boots. This will take you into the BIOS. Look for the hard drive section and make sure the laptop has detected your primary hard drive (the one with Windows on) and that it is selected as boot disk priority 1 in the boot sequence settings. If it says something like "NO IDE DEVICE DETECTED/NO SATA DEVICE DETECTED" then refer check your hard drive is installed and physically seated in its socket.
4. Remove all flash drives/printers as you boot up the laptop.
5. You BIOS may be corrupted and may need to be reset. (See below)
All laptops have a CMOS battery. The main purpose for the CMOS battery is to store the system time, date and BIOS settings even if the computer is turned off or the main battery dies. Individual Acer Aspire laptop models differ somewhat, but the general steps are the same when replacing a dead CMOS battery.
Before you start
1) Read through the owner's manual for your particular Acer Aspire laptop to determine what kind of CMOS battery you have.
2) If it is damaged or faulty purchase the battery through Acer or a local or online computer parts dealer.
3) Turn the laptop off and unplug it. Also unplug any external hard drives, cameras, or other external devices.
4) Turn the laptop over (bottom facing up), then touch something metal to remove static charge.
Removal of the CMOS battery.
Remove the Phillips screws that secure the motherboard cover (refer to your owner's manual if necessary), then release the cover from the clips on the bottom of the plastic casing. Lay the cover aside then locate the CMOS battery cable on the right side of the motherboard. Unplug the cable then remove the battery.
The battery should look something like this:
Leave the battery out for up to 20mins. (Once the charge has left the motherboard it will erase all BIOS settings.
Re-inserting the battery.
Plug the CMOS battery cable into the motherboard. Slide the battery partially under the laptop casing (somewhere to hold it in place), then align the cover with the slots on the bottom of the laptop housing. Replace the screws then turn the laptop back over.
1) Turn the laptop on.
2) Enter your BIOS (usually by pressing the "Delete" key) before the operating system loads.
3) Follow the BIOS prompts or refer to your Acer Aspire owner's manual to reset your time, date and desired system settings.
Reason: Anytime the CMOS battery is unplugged for more than a few seconds your BIOS will be reset to the default manufacturer settings. If you make any changes to the BIOS that cause problems with your Acer Aspire, unplug the CMOS battery for 3 to 5 seconds (I find a good 'ol 20 mins does the trick if your unsure) to correct the problem.
6. You BIOS may have become corrupted and a re-install may be necessary. (See below)
Head over to the Acer downloads support center here.
Select your laptop model:
2. Aspire One.
3. The model.
Then click confirm.
Then at the tabs at the top click BIOS.
Download the BIOS.
Read the included documentation first (if supplied)
You'll need to copy the downloaded BIOS files onlto a bootable USB device.
1. A USB device.
2. The BIOS (that you've already downloaded).
3. The tools required make the USB device bootable.
I've found a neat tutorial on the web that explains how to make your USB drive bootable. Check it out http://www.evga.com/forums/tm.aspx?m=15265&mpage=1
(skip step 8 as you hav ealready downloaded your BIOS from the Acer support site, but read all about renaming it to BIOS.bin)
Once the drive is bootable, copy over the BIOS files as to the tutorial's instructions.
Reboot your system and make sure that the USB in inserted and set ans primary boot priority 1.
Your laptop should now update/reinstall the BIOS and reboot. Remove you USB drive as it reboots and it should be fine. If however this doesn't work then it may be a hardware failure and will have to be looked at by a local technician.