I just removed the stupid Win 7 Security 2012 virus using AVG, and now I can’t open any .exe files. It just brings up the “Choose an application to open this file” menu. It does this because the virus made it so whenever you clicked an .exe it opened the file by launching the program, a very clever hijacking scheme. Now that the virus is gone, there’s nothing left to open .exe’s with. What can I do?
Also, a bunch of paths for system files are missing. For instance, when I try to lauch Task Manager by clicking an icon, it says tskmgr.exe (or whatever it’s called) can’t be found. Same with Explorer, I closed it and when I tried to relaunch it by clicking New Task and running explorer.exe it says THAT’s missing too. I know it’s not actually gone because it still runs (Task Manager can be opened using ctrl+alt+del, and Explorer is just running as I’m typing this). What can I do to fix the problems the virus left behind?

Download RKILL from here: http://www.bleepingcomputer.com/download…
This will reset the file associations and should fix your problem with the .exe not opening.
Hope that answers your question.
You did not use the correct removal guide, scroll down to the automated removal instructions, and run all the tools in this guide, it will solve your problem, and you will be completely rid of all traces of this malware:http://www.bleepingcomputer.com/virus-re…
Try restarting your pc, also have sector check on startup. Try another malware or adware program, might still be infected. Try the one from the website provided, it scans your whole pc for free = )
Put you windows cd in and select repair windows.
To eliminate your problem, try doing this:
1. Click Start.
2. In the Search box, type CMD and then press Enter.
3. Type attrib and press Enter. Command will return drive files you should “cure”.
4. Type command attrib -s -h -r *.* This will simply reset all the files in the drive.
5. Delete all the files having the SHR attribute, just type del file.extension
6. Restart your computer.