Your personal data will remain intact. You have to boot into DOS in order to format the active partition. The reinstallation will replace your system files, which means you may have to reinstall your browser, if you were using a newer version. But your photographs, MP3's, etc ... they should be right where you left them. Unless, for some strange reason, you've been keeping them in the System folder!
Note: If Windows is really screwed up, or if you have been running the operating system for a year or more, your computer will run better if you go ahead, back up your files, and do a clean install on a formatted partition. The Windows Registry gets clogged up with keys that lead to nowhere from uninstalled programs ... that kind of thing. People have been reinstalling Windows on a regular basis to keep their systems healthy for years. It's one of the things you live with if you want to run a version of Win9x.
Toejam31
<font color=purple>If there was a reason for everything, having faith would be redundant.</font color=purple>