The way they take out the virus scanners is by a registry entry that changes the exefile string to point to the virus.
This means you cannot open the registry either, to edit the change (or indeed any other program). However, there is a little trick I often use. Find your file regedit.exe and rename it to regedit.com Since a .com file is also executable, the registry will now open by running the renamed file. Same can be done with your virus scanner to make it run, rename the .exe file that opens it to a .com
I have not used the tool on this one, but would almost guarantee it will be a .com file
