A lesson I don't like seeing people learn firsthand is that hard disks are terrible places to keep what you can't lose. Installing an OS just increases the risk factor that all will vanish by a number between 100 and up over normal risk numbers.
I just did some 2000 upgrade last week for instance and it went smoothly (YMMV!) and for me, all I needed to fix after was to go get audio, video drivers and install an updated antivirus. I still need to install some CD Recording software...
Remember, you only lose what you don't protect.
I want to upgrade to and install Win 2000 Pro. I am currently running Win 98. To install am I going to have to reformat my hard drive or can I install over Win 98.
If I have to reformat what files other then my data (my documents), favorites, and zip should I back up before installing?