Click Here to open a thorough guide to doing a clean install of XP. Skip the first part and scroll about a third of the way down the page to the heading, "Steps to Clean Install XP."
Just copy all your data files (documents, address book, email messages you may want to keep, music, pictures, browser Favorites, etc.) to the second harddrive. If you use bookkeeping software, like Quicken, don't forget to back up its data onto the second drive, too.
I recommend you copy rather than move the files. That way, if Windows hiccups during the transfer, you'll still have the originals to try again. If there's a problem during a move, you run the risk of losing the files you're trying to move.
I make a folder on the drive I'm backing up to and copy all the data into that folder so they will be easily found and retrieved later.
You cannot save programs, they will have to be reinstalled.
Once Windows is reinstalled and all updates installed, you can copy the data files back to where they were. In the case of Outlook Express or Outlook, it's better to import the old files back into the program.