I have install Service Pack 2 two days ago and now 1 or 2 times /day the all system hangs , including my usb whell mouse.
After restart everything is fine
i do not have install a new software or harware .
What is the possible cause of this issue.

Any idea, Please

Two things to check:

1. Event Manager: look under all 3 tabs for red X errors that relate to the hang time.
Double click to see error message. Post back the exact errors.

2. Device Manager: look thru your devices for any yellow !.

Both these services are found by Right clicking "My Computer" then click "Manage".

This is a problem posted quite a bit but we need more details to pin it down.

have you tried re-instaling sp2?

Uninstall Sp2 Use System Resotroe To Go Back To A Known Good State For Your Pc Then Reinstall Sp2
Good Luck