need help to remove disorderstatus.ru differentia.ru

I keep receiving two popups from avast.
Both from C:/Windows/system32/msiexec.exe
the first one is http://disorderstatus.ru/order.php
and the other one is http://differentia.ru/diff.php
I dont know where to begin to delete them.
This happened after using a friends Flash Drive on my pc.
Please help

http://forum.avast.com/index.php?topic=53253.0

This happened after using a friends Flash Drive on my pc.
Meaning your friends computer is also infected, You may send him here for cleaning help

Flashdrive protection: MCShield http://www.mcshield.net/
you find instructions for it in the guide Eddy gave link to