Dead End in Trying to Remove Malware

I believe my PC is infected with the Antivirus 2009 malware, and I am running out of solutions to remove it and am in dire need of assistance beyond my knowledge level.

Two days ago, I was using Firefox browsing the web when my desktop changed over to the "your computer may be infected" graphic signaling the start of the problem.

I noticed multiple tasks running in Task Manager right away that I recognized as malicious and ended them. I then tried to run AdAware to remove the perceived spyware, however I was given a strange error message. I have SpyBot, as well, and I ran in, however it did not identify or fix any of the problems, and it noted an error when trying to connect to update definitions.

Frustrated, I went back to Firefox and found that my webrowsing, as well, had been compromised. I noticed odd subdomains flashing on the lower left status bar when I tried to search for solutions in Google, and when trying to get to lavasoft.com, or sites I know containing spyware removal, or even spyware forums, I found that it was redirecting me to advertisement sites upon clicking, and even when I tried to cut and paste the link a "connection could not be made" to any of these sites.

After a couple of hours of research, I found several solutions to the problem posted in various locations. Most involved finding and deleting certain file names, registry entires, etc., which I did, without any success. Many of the solutions also suggested to download various anti-malware programs, which I attempted to do.

However, I am unable to install any of these programs thus far. In addition to AdAware and SpyBot not working, I figured out how to get by the blocked sites and downloaded Malwarebytes, Superantispyware, and a couple of other common programs. After clicking the install file for each one, however, I almost immediately receive error messages that the file is corrupted, invalid, should be redownloaded, or is not a valid win32. The error messages are pop-up dialog boxes that are often oddly worded or missing periods, or otherwise sketchy.

I tried PC Doctor, however it would not even start up, and System Restore oddly had 0 restore points available to use.

I have seen many people on forums affected by Antivirus 2009 solve the problem by running anti-malware software. However, I have not seen many where no programs can even be run to begin to fix the problem. As such, I am not sure if it is actually Antivirus 2009 on my system or another form or another malware or both.

This has left me in an awful predicament where I have a serious malware infection and no way to remove it with programs at present, and presumably no way to install new programs to fix the issue. I am assuming I am going to have to either find a detailed way around this problem or figure out how to prevent the malware from shutting down the installation process of programs in order to even begin removing the infection.

I am essentially lost as to where to go to here but still desperate in trying to prevent having to reformat my computer or call a $300 computer repair service.