hey thank you for entering here .. i hope you would help me with this .... my problem is when i start windows it crashes immediatly and stucks so i do (ctrl+alt+del) to enter the task manager and log off the user .. and log on again and the windows starts normal but with some errors like msn error (windows live communication platform) and some programs that doesnt work even if i remove or setup ... so i formatted my pc and deleted everything in the hard disk empty !!! i setup the win xp sp 2 and the problem still there ...... but i deleted everything in the drive why is thaaat ?

thanks .... i hope you would help me

You most likely have either faulty ram or a faulty hard drive. Out of the two, faulty ram seems more likely to me.
Google and get memtest and run it for at least 7 passes. It will take many hours to run so you will need to be patient. If memtest comes up with any errors at all then your ram is faulty and needs replacement.

mm .. i did what u say .. but 0 Errors .. i let the program work for at least an hour .. nothing ............

To run 7 passes should take more than 3 hours.