HELP!! I need assistance in removing viruses or smth.

Help me plssss!
November 29, 2015. I keep on getting warnings from my anti virus (Avast Free Antivirus) every few seconds.

URL: http://disorderstatus.ru/order.php
Infection: URL:Mal
Process: C:\Windows\System32\msiexec.exe

and
URL: http://differentia.ru/diff.php
Infection: URL:Mal
Process: C:\Windows\System32\msiexec.exe

I tried asking my cousin for help and searching on what to do about it, but its no use. Its getting annoying. Pls, help immediately.