Actually it's not too difficult to get rid of, especially in Vista and Windows 7. I work at an IT desk and see it all the time; once you figure out a procedure to follow, it's easy to get rid of. Here's how I do it:
1. Copy the entire contents of the quote at the bottom of this post into Notepad, save it as a .reg file on the desktop (select "All Files" so Notepad doesn't tack the .TXT extension on). This will delete the problematic entries from the registry and allow you to run .exe files normally again. (You can go in and delete them manually, but it takes some digging. This patch works every time and takes seconds to use.
2. Reboot into Command Line Safe Mode (so the thing won't load)
3. Run msconfig (it's built into Windows)
4. Go to the Startup tab
5. Disable anything trying to run out of any of the folders under the C:\Users\[your name]\, C:\Profiles\[your name], or C:\Documents and Settings\[your name] directory. Check all the other entries as well, because some manage to work their way into C:\Program Files. (I have seen this on XP a lot but never on Vista and Windows 7 with UAC enabled, unless the user was a fool and ran Firefox with elevated privileges).
6. Run Regedit (type it into the command prompt).
7. In Regedit, click "File -> Import" and select the .reg file from step 1. Allow it to merge with the registy. Once you see the "Sucessfully merged" message, you can close Regedit. (You can delete that file if you want, but I recommend putting it away somewhere so you can use it in case you get hit by a similar malware infection again.)
8. Restart your computer normally. The malware
shouldn't run at this point.
9. Right click the malware's shortcut on the desktop (it usually has a shield icon and has a funny-sounding name like "Security Tool" or "Total [XP/Vista/7] Antivirus 2010")
10.
XP: Click Properties, then "Find Target".
Vista/7: Click "Open File Location" in the context menu.
11. You should now be in the folder with the malware .exe. Go up to the parent directory and delete the entire malware folder.
Your computer should be fine now! At this point, I recommend installing
Malwarebytes' Anti-Malware and allowing it to perform a full scan in case there's anything we missed. A full scan will take a couple hours to perform, but you can shorten that by running a drive cleaning utility like
CCleaner so it doesn't have to waste time scanning temporary junk. (Get the portable or Slim builds; the normal one includes the Ask.com toolbar.)
Windows Registry Editor Version 5.00
[-HKEY_CURRENT_USER\Software\Classes\.exe]
[-HKEY_CURRENT_USER\Software\Classes\secfile]
[-HKEY_CLASSES_ROOT\secfile]
[-HKEY_CLASSES_ROOT\.exe\shell\open\command]
[HKEY_CLASSES_ROOT\exefile\shell\open\command]
@="\"%1\" %*"
[HKEY_CLASSES_ROOT\.exe]
@="exefile"
"Content Type"="application/x-msdownload"
