Here, please run the HiJackThis from Trend Micro Site, and rename that setup to Crusty.exe, run it and save the log. I would like to see it 
... then when you did that give us your Steam ID and password so we can make sure that everything is fine with it.
Also don't log on it for some days so we can VAC ba... erm... VAC clean all of your games.
Kthx
Just run some antivirus and malware detector (ESET Nod32 Smart Security). Boom, done.