Posted 10 October 2009 - 11:45 PM
Some types of malware will disable MBAM (MalwareBytes) and other security tools. If MBAM will not install, try renaming it.
Before saving any of your security programs, rename them first. For example, before you save Malwarebytes', rename it to something like MBblah.exe and then click on Save and save it to your desktop. Same thing after you install it. Before running it, rename the main executable file first
Right-click on the mbam-setup.exe file and change the .exe extension to .bat, .com, .pif, or .scr and then double-click on it to run.
If after installation, MBAM will not run, open the Malwarebytes' Anti-Malware folder in Program Files, right-click on mbam.exe and change the .exe as noted above. Then double-click on it to run..
Open up command prompt, type in following commands:
XP >> click the Start menu at the lower-left of your computer's desktop and select "Run". Type cmd into the Run box and click "OK".
Vista >> click the Start menu at the lower-left of your computer's desktop and Type cmd in the search box.
Try using a System Retore Point prior to the date of infection. You may be able to update and run MBam. Note this did not remove the malware.
Windows XP System Restore Guide
[credits to boopme]