I have recently installed AVAST antivirus home edition on my and since them my PC is crawling. It is having most the time 100% cpu usage and found that ashserv.exe is causing that. It is I think related to AVAST becuase when I stop or terminate it, Avast says, no service available ie no virus protection.

Is it my PC or problem with Avast ?
My PC is p4 -2.6 , 512 mb RAM

I too found AVAST problamtic once. Its just that their virus removal engine is too much CPU hogging. The solution is that try other antivirus like AVG or Norton.

I too face the same problem. But I think AVAST is reliable and catches more viruses, to my knowledge!

Well.. now I use Avira Antivirus, one of the best antivirus I ever used and its free for personal use as well lite on system.