if that doesn’t work block the program from the internet and uninstall it.

http://download.cnet.com/AVG-Anti-Virus-Free-Edition/3000-2239_4-10320142.html

combofix
smitfraud fix
malwarebytes anti-malware

those should get rid of most infections

to boot into safe mode hit F8 while the computer is booting up.

Future Protection use this wizard to recommend security protection for your system:

http://www.techsupportalert.com/secwiz

or go to safe mode and then do the above:

To get into Safe Mode with Networking:

1. Log out and reboot your machine.
2. When the machine starts the reboot sequence, press the F8 key repeatedly.
3. Select Safe Mode with Networking from the resulting menu.

Or Manually:

Terminating the process:

1.I verify that a Rogue is present. This isn’t hard, since it’s usually popping up just about every few seconds.
2.Click CTRL-ALT-DELETE (if it’s available)
3.Click Task Manager
4.Click Processes
5.Find a process that usually contain all numbers. For example 2342342.exe. If you do not see all numbers then your rogue has a name like…SystemSecurityPro.exe or GreenAV.exe…etc.
6.Select that process and click end process.
7.At this point the rogue process has been terminated.
Removing Rogue Anti-virus that is named with random numbers.

1.Click Start
2.Click Run (or for Vista type in the start search box)
3.For windows xp type: C:\documents and settings\all users\Application Data and click OK. A window will open containing a folder with about 8 numbers. Your Rogue is in there. Delete that folder.
4.For Windows Vista type C:\users\all users in the "start search" box and click enter. Your randomly named folder with about 8 digits should be in there. Delete it.
Removing Rogue Anti-Virus that has a name like System Guard Pro, AV2010, etc

1.Open Windows Explorer.
2.Open your C:\ drive.
3.Open Program Files
4.Find the Rogue and Delete the folder.

If not seek an expert. Good Luck!