sasser like behavior

[gulembo]

my PC every some minutes hang for few seconds then the screen goes blank  or flicker and  keep running normally, sometimes hangs for longer period and I minimize the program running and maximaze it again it keep running and this goes worts when  I go on the net , if I tried to remove a program it hangs and i have to reset otherwise it won't  come off from it. I ran a scan and nothing come up.

I have avast 4.5 version and is up to date.  please advice

[Eddy]

I suggest you start with making sure that your system is clean. Click on the link in my signature and follow the instructions in the malware removal section.

[DavidR]

I have avast 4.5 version and is up to date.  please advice

The current version is 4.6.603 so it would appear that you are not up to date.