1st, I dont think this is the correct forum for your question, I expect it will be moved...
However, I'm assuming you have two partitions/harddisks, reformat the XP version your not using. Move all the files you want to keep to the other partition first.
For reformatting, go to 'Run Program' the little box where you can enter a file name you wish to execute (I'm not sure what the english name for this function is).
Type: cmd.exe
Hit ENTER, you'll get a nice DOS-like window.
Now use the 'format' command as appropriate, see:
http://www.microsoft.com/resources/d...us/format.mspx
KR,
Rogier