Hi, After booting, wauclt.exe takes almost 99% of CPU time and no downloads I need to put on the system may take place.After I end wauclt.exe on task manager then CPU becomes normal (System Idle Process takes 98% time of CPU)thus I can resume norlmally.. But everytime I restart, the killing of the wauclt.exe process is necessary. Although my virus program (Ca eTrust)doesn't find it I suspect that is worm or trojan that my virus program cannot perceive. Thanks for your help in advance...

The reason why CA's eTrust doesn't find anything is because because wauclt.exe is not a virus but a worm, specifically of the w32.gaobot.ajd Worm family. i_XpUser

And JSYK, wauclt.exe is not to be confused with wuauclt.exe - a (legitimate) process that manages automatic updates for Microsoft Windows. This process continuously checks for the latest updates and uses the Internet to do so. This program is important for the stable and secure running of your computer and should not be terminated, but I do not believe it should be hogging 99% of your CPU resources either.

Thanks to xpuser and sabertooth for your comments. The first comment has been useful to me. I hope sabertooth would never meet that worm, otherwise he is going to believe about what he has disbelief now. Do you XpUser know any tool that removes aforementioned worm? Thank you very much in advance...

When I try to update from microsoft site, wauclt.exe takes 99%CPU time then the update virtually stops, waiting for almost one hour without doing anything. The I kill wauclt.exe, thus update microsoft page reports a fault(sensible to me)since wauclt is necessary for updating. But I had been updating microsoft products up to last month. Is there any comments on this point? Appreciated...

Do you XpUser know any tool that removes aforementioned worm? Yes - this is it. I have to caution you that the removal procedure for a worm is not that simple. You can opt for the W32.Gaobot Removal Tool available on that page. i_XpUser