How To Reinstall Windows Without Losing Anything

1- Start WindowsXP
2- Go to the location of your source files
3- Run WINNT32 /unattend
For example, D:\I386\winnt32 /unattend ( copy & paste this command into the RUN box, then press ENTER ) Your computer will do the rest.
Or,
Start > All Programs > Accessories > Command Prompt.
Copy & paste > D:\I386\winnt32 /unattend
Press Enter.
If you have i386 on your drive, you can replace D: ( if D: is your cd drive ) with the location of it.
I've often need to do this to repair something that had gotten corrupted and didn't want to do a clean install.

D: is the driver letter where your windows XP Cd is
if D:\I386\winnt32 /unattend doesn't work then try : d:\winnt32 /unattend.