How to fix system restore point issue in XP SP2?

Hay Guys,
I am running XP service pack 2 and having a critical issue while using it. The issue which has occurred to me is that I cannot restore my PC to any previous restore point. Whenever, I want to restore via restore wizard it starts to restore but in the end computer gives a message that no change has been made. I have tried this particular trick at several restore points but none of them was restored successfully.
To solve this problem I have de-fragmented my local disk C already but no gain. I also have fixed my windows registry at least in my theory with the help of C cleaner application. I even have checked the disk via chkdsk command but the issue is still alive. I have give up my efforts now to solve this issue because I do not know that what else should I do to solve it? And now I do not have enough money to re-install the genuine XP as I already have done two to three times in a single month due to this problem.
So, I want to inspect that how to fix system restore point issue in XP SP2?
Kindly help me if you can. I shall be happy to provide more information about the issue if demanded. Thanks and waiting for your suggestion.
