trouble with partitions

I have an HP in which i didn't realize that there is a system restore installed on the computer. I used the windows XP disk to reinstall it, and when i did that i installed it in the "HP restore" parition (which is only 5GB big). now my whole operating system and programs are installed in this 5GB vs. the 100 GB i have. How do i alter this and put it back into order without reinstalling? Please let me know if u can help by reposting r emailing me at [email protected]. i'd greatly appreciate it

Install this partition manager (http://www.ranish.com/part/) and resize the 5gig one to take up all the space.