
Hey Fren,
Well, the short answer is, you can't. Unfortunately, instead of repairing your existing windows OS, you installed another copy of it. From your description, you did the same thing when you upgraded to XP. Consequently, you are taking up the HD space for three versions of an operating system, instead of one.
Now in regard to your important files. If they are actually important to you, you should have them backed up, and regularly. Preferably once a month, either to CDs, an online backup service, a separate harddrive, or a separate section of your current harddrive.
The best advice I can give to you is to completely reformat and reinstall your OS, operating with multiple versions of XP is notoriously unstable. However, there is a fairly painless way to move your files to a safe place while you are reinstalling. There are others, but I recommend using the online storage service
X-drive. They give you a full thirty day trial, there program is easy to use, and it works just like moving files from one drive to another. The only trick is to discontinue the service if you don't want to keep it, or you will get charged.
The other advice I have for you is to follow the instructions for installing XP on a single harddrive. It is a multiple partition tutorial that keeps XP running really smoothly. The instructions are in my signature. Read through the entire illustrated version first, then print out the printable version to follow as you go through the process.
If you need any help with any of this, just let us know.
Look forward to your reply,
TTFN
LGW