Internet Security 2010 is a particularly nasty trojan - it is one of many fake anti-virus/anti-spyware programs. It will not only refuse to let you use real anti-virus programs like AVG, it will tell you that they are themselves a virus and prevent you from visiting their respective websites.
The instructions here are very useful for removing IS 2010 from your computer. Make sure to download and run rkill first before trying to remove IS 2010 or you will have problems.
As always, MalwareBytes is one of the best removal programs out there. It is best to do the removal in Safe Mode to be absolutely sure you get it all. Once done with the removal, do yourself a favor, and run the following command on the next boot if you are running Windows XP SP2 or higher:
netsh winsock reset catalog
This will repair your TCP/IP settings and LSPs. IS 2010 or one of its bundled nasties has been known to corrupt the TCP/IP stack and prevent ethernet and wireless from working properly on reboot. You can read more info here on what this command does exactly.