First of all, thank you for spending time trying to help me with this. I have a desktop with windows xp and sp2. I've had this PC for over 3 years now, I constantly leave it on the whole day and night to download stuff. Yesterday, I turned the PC off because I had to go to school and when I came back, the screen was stuck on the Intel logo. There was a 'BIOS settings:f2' at the lower right of the screen. Ive tried pressing f2, delete, tab, and other keys to no avail. What should I do?

When you turned it off origianally, did you go through the sutdown process?

Restart and see if you can get into BIOS right away before screen freezes by tapping the F2, if you can get in, reset BIOS defaults and reboot

As if it will do nothing at this point, turn it off and try to start again and start tapping the F8 key to see if you can come up to the option menu - choose Last Known Working Config

See if any of this helps

Thanks for the answer seahwk! Strangely enough, the computer resolved its problem by itself (I did hit it once or twice at the side). I have an unrelated question though.. I have a habit of leaving the computer for long periods of times.. sometimes whole weeks in which the computer is just turned on and downloading files. Would this destroy the BIOS or the computer in general? (like the heat or something?)

Shouldn't be an issue. But I would suggest doing a shutdown or a restart every so often.
Personally, my XP is on constantly but I do find by restarting the operating system does help as far as clearing cache, files in memory and basically resets your system state like when you first turn on your PC.

By doing this, you should notice a slight difference in performance as in time, the OS will tend to slow down

So at least restart your PC every so often, like when you get to it for the first time each day, just go to the restart button. You should be OK