I recently was plagued with a Adware/Trojan Virus masked as a: C:\Windows\System32\ati2dva.dll

I tried everything, nothing worked. I could not delete the file either manually, in Safe Mode, Command Prompt Safe Mode, and either within the Registry {regedit]. I tried BitDefender System check, Norman Malware Removal, Spybot, and MSRT, with zero luck, they only program that actually saw this was BitDefender... which blocked it, but was unable to delete it.

After doing a Google search, I found that many people were having the same problem. I stumbled upon some solutions, none of which worked. A software solution called Prevx, and after saying in particular they could move that exact file, I fell victim to the old trick, of showing me they found the virus, but hey now I have to pay $29.99 to complete the removal process.

I don't pay for stupid solutions such as that, and I don't even know if it would have worked. So I tried a program called "Hijack This", you can find it via a http://www.download.com search. Basically you can run a scan, and target a suspicious file (and it found the file as suspicious), I then targeted it, but it was to slick. No luck.

I then tried "Avenger2", see below for detail, which is a custom program someone wrote, to basically have it execute a command pre-boot and delete the file in particular. It then zips/contains it and drops it into a specific location. No luck!

Avenger: http://swandog46.geekstogo.com/avenger2/download.php
Pasted this into the prompt: Files to delete:
C:\WINDOWS\system32\ati2dva.dll

Then I gave a program called "ComboFix" a try. What a gem this thing is.
ComboFix: http://www.bleepingcomputer.com/combofix/how-to-use-combofix

I created a new TXT file via Window's Notepad, and pasted this information in there (Registry portion not authentic).

File::
c:\windows\system32\ati2dva.dll
Registry::
[-HKEY_LOCAL_MACHINE\~\Browser Helper Objects\{63608544-DEE0-49CA-BE63-C03E148FABBF}]

The information you pasted, is determined by the actual file location, see "File::". And then the registry location, see "Registry". The registry information will fluctuate, and you can't simply copy/paste the registry path above. You need to go to regedit [Start>Run>regedit] and click the root directory and search the file "ati2dva.dll". Then copy the folder structure up unto the long hex number.

You drag the TXT file onto the ComboFix executable. It will open a window and warn you about running Virus software simultaneously with the following processes it is about to perform. It will warn you twice, I ignored the warnings, and let my Virus software run. I did this because my Virus app could not delete the virus that I was in the process of deleting, but it was able to block it from attacking my computer, just not delete it (which would attack sporadically, yet be blocked.)

ComboFix, will then check your Windows Restore software, and if you don't have it, it will actually connect you with Microsoft for built-in download with the program itself. It then runs it course, reboots, and creates a log file. I forgot to mention it found 4 other suspicious registry issues, and repaired other areas as well.

Love this program!