The reasons everyone is coming up with different suggestions is that machines use different BIOS code, and each one has its own scheme. I have seen the bios screen acces via F1, F8, F12, F5, ESC and DEL.
The best idea was Ron Jeremy's. Most BIOS's will display the key at boot, although it can go by pretty fast.
The point about changing boot order is correct. You may have to search around the bIOS screens to find it.
We may be getting ahead of ourselves, though. Did you just try inserting the main recovery disc and see it it will boot? You may not have to do anything.
I'm not sure that the install bare windows is the right answer for someone not too experienced with this. Sure, you must then remove the junk (if it is important), but with a bare windows installation, you will likely be all over the net searching out new device drivers. Not for the faint of heart.
Matt, you are seriously suggesting Linux for a 6 year old on a computer administered by a novice? Riiiiiight!