Hi Billie,
I would recommend AVG to protect you from Viruses ONCE the computer has been cleaned up and is running properly , however to remove the virus you will probably need to run a combination of anti virus and rootkit removal tools.
Unfortunately as viruses have become more advanced, gone are the days where you could run a simple scan and things are fixed in 10 minutes, most of the time viruses are very difficult to remove and require a degree of experience at doing it manually and knowing what should and shouldn't be running on your computer.
Also, as you are probably aware from this virus, you are not able to run or install programs as the virus seems to have blocked you from installing .exe or msi extensions, again this will mean just simply installing Norton and running a scan will not work. You can try in safe mode by pressing F8 during the boot sequence, but you will need to use "Safe mode with Networking" to enable you to update the anti virus definitions of the software you choose, other wise you will not be using the most up to date version.
I hope this helps.