Well... sure, I could just reinstall windows, I did it before on my computer, but there are two problems with that. First, all the registry will be wiped, so much programs won't work anyway, and might be hard to uninstall, second, it might be a virus that she got, so just reinstalling windows might not be enough, but thanks for the advice, I'll keep it in mind tomorrow.
I already asked if it was ok if I reformatted, and she said it is, but I would like to have another solution, of course.
As for windows itself, I'm partial to Windows 98. It allow me to play all my old dos games, and do the job just fine. I very rarely get errors message, maybe only one every few months, and I use my computer all the time.
Also, windows 98 is the only one I own, so my choices are a little limited...
Well actuall, I don't even know what version of windows she own.