you don't hold F8 down, you press it once or twice when the computer boots and before the splash screen.
Good call on the link malmental. Holding the F8 key after hearing the single BIOS beep usually works too, unless "report keyboard errors" is turned on in the bios, then you get the "keyboard stuck" error.
Yes, the timing can be a little tricky on pressing the F8 key. The link malmental posted will work for you.
File system corruption may also be a cause. Try running a chkdsk on it.
Open "my computer"
Right click on your drive and select properties.
Click/select the "tools" tab
At the top you will see error checking with a "check now" button.
Check off "automatically fix file system errors"
You may get a warning about this being a system disk or what not. Just tell it to run check disk on next reboot, then reboot the computer. It should run a check disk before booting into windows.
total reformat of hdd and re-install windows.
odds are the file was corrupted or had hidden virus in the first place.
there might be a 'third-party' software removal program but that's something I neve had to worry about so I don't know.
your laptop my have the function to restore to it's original state, called destructive repair or something like that.