P.S.: Under the "Advanced" tab I mentioned, change the settings for "Error Reporting" to Disable-but-notify. It's actually less crashy that way. And from any window when browsing disk contents, go to Tools->Folder Options, "View" tab, and tick "Launch folder windows in a seperate process" for additional stability.

Another thing, if you use XP or something with fast-user switching... Make at least two accounts. One normal account, one Admin account. I usually make the admin account have a wallpaper saying "DO NOT USE THIS ACCOUNT EXCEPT FOR..." Teach them to use the non-admin account for all day-to-day work.