Expanding svchost.exe

Hi guys, i am a new guy here, but i need help. I am currently using windows 7 ultimate edition. One day my Kaspersky Antivirus told me that the file svchost.exe is trying to download a strange .exe file from the net,which seemed to me as a virus, so i concluded that the file svchost.exe had been infected by a new kind a virus ( kaspersky couldn't fix that)

the question is : How can I restore the original svchost.exe from the windows 7 disc through the system recovery ( booting from installation disc), because when i tried to extract it by using 7-zip extractor in win32 environment, the virus could detect it and then infected it again! so i need to restore it from the environment which the virus can't be activated. PLEASE HELP.

any suggestions will be appreciated. Thanx.

unfortunately, i don't have any restore points at all

Do a virus scan with an online scanner like Eset or Panda. Another thing you can do is to download and scan with malwarebytes antimalware.

i have tried both eset and panda, and you may notice that i've tried it with kaspersky 2010 pro edition!

nope, well, i still can't use it however since i haven't made any images at all....

lukaswrites,

can you tell us exactly what is happening on your machine? Other than the kaspersky message, have you noticed any wierd behaviour? Also what is the name of the strange file that svchost was trying to download?

well, according to the kaspersky antivirus 2010, svchost was trying to download file http://83.133.124.199/inst_n107.exe ,and not only svchost.exe that was trying to download this file, but ALL of my browsers seem has been infiltrated by this virus, and when i used google search, firefox, opera, safari were detected to access random phising URLs. any idea?