I'm in need of help

....I thought I knew what I was doing BUT I've recently become infected with a virus and some spyware, which I though ti had cleaned but which seems to be EXTREMELY persistent. I think I picked it up from a media site and my PC slowed to a crawl, so I did a Sophos (which is absolutely up to date!) scan which took about 13 hours to do a 40GB HDD and picked up a few things and then cleaned them...

But it seemed to be hanging around, so I did another scan, and picked up that I was infected with:
- Troj/Virtum-Gen virus
- Clickspring adware

I try to clean these up but they come back. In addition, my URL address bar icon for Google in IE has turned into a weird, blocky T5 logo, and it isn't like this in Firefox which I also run...I think I might have been hijacked but I don't know, so I really want some help please (pretty please in fact!!)

I'll attach my Hijack This logs (run from a folder on the C: drive) and a shot of the weird IE logo, if you can spare teh time, I'd ge grateful for anyone who can help me to get rid of this infestation...many thanks in advance

M