Recently my computer has been attacked by Virtumonde (or Virtumundo). Symptoms first appeared when ads started popping up while using my internet browser. I then attempted to download Malwarebytes, however when I installed the program it deleted the mbam.exe file immediately after installation, making it so I could not use the program. However, I was able to pull a couple maneuvers and get the mbam.exe file on my system. I have run the Malwarebytes program several times (with and without being connected to the internet and having system restore on/off). Each time, it finds approximately 10 infections related to Virtumundo, and asks me to restart. When I restart my computer, all the processes that normally start at startup bring up an error box saying that some .dll file (the name of which is arbitrary and seems to change after each time I run Malwarebytes and remove it) is not a valid image. I can run malwarebytes again and it finds nothing. However, my computer runs much slower and seems to be using a lot more CPU than normal. Once I get online, the virus re-infects itself and I am back to square one.
I have attached the most recent HiJackThis log that I made before writing this post. I would greatly appreciate any help!