Trojan horse Crypt_s.CCD and Luhe.Sirefef.A

I run AVG antivirus on my Windows 7 Dell computer. I have recently been infected with these Trojans. AVG blocks the threats but I get this message

Cannot be removed. Access is denied.

I have tried to download an updated version of AVG - and get the message that the download is infected with a virus and has been aborted. I get the same message when I try to download other antivirus programs as well. I also got the same message when I tried to follow the instructions on this site for dealing with this problem...

I live in a rural area with and don't have easy access to a computer technician who could take care of this.

Can you help, please?

Thank you.

via Bleeping Computer Last 20 Posts http://www.bleepingcomputer.com/forums/t/510838/trojan-horse-crypt-sccd-and-luhesirefefa/