AFAIK you need to build a provisioning template that
1) Backup personal data
2) Apply OS image
3) Restore applications (using SWD)
4) Restore personal data
For backup and restore you shuold use a backup tool; LANDesk has a good one but I preferr Microsoft USMT.
Complications are usually in the "back up personal data" ... it depends on whether the user (or users? ) were "good" and kept it all in "My Documents" or some other named share, or if they saved their stuff all other the hard-drive.
If it's just a single PC, go and have a look at it beforehand.
If it's a bunch of PC's, send a message to the users, tell them to move all their personal data to "some directory" ( "C:\Data\" for instance) and anything they don't move will be lost. (That said, it's best to take an image of those PC's BEFORE re-imaging them, because I'd put good money on the users forgetting to back up "something or other of critical importance", and then you can look good because you've gone the paranoid route and accounted for their oversight)
LANDesk EMEA Technical Lead.
There's an online service that does just that - reimages your PC without touching your data and applications (even if their not in the 'my documents' folder).
It works only on XP machines at the moment though.