I have got Win.XP Pro. When i click on the cisk clean, it opens up but it does not run. can anyone help Please.

Thanks.

Does it freeze while compressing old files?

This is a common error.

Here is the Microsoft Page with the manual fix:

Disk Cleanup Tool Stops Responding While Compressing Old Files

This is an automatic fix via Kelly's Korner:

Disk Cleanup - Compressed Old Files Freezes (Line 48)
http://www.kellys-korner-xp.com/xp_tweaks.htm