James,
I set up Windows 8 on my work laptop mostly because some of our clients are starting to show up with the OS, and felt it was time to, for lack of a better phrase, deal with it. AVG 2012 initially rolled out, but I had to completely disable Windows Defender. After about a week of it showing no issues at all, I suddenly began receiving Windows notifications of compatibility issues, and AVG would always start with an exclamation mark over the icon. I've tried adjusting compatibility settings on all .exes with no success, so today I decided to just get rid of it. I found that it will not uninstall from Programs and Features, nor from the Kaseya console. I finally removed it using the AVG Removal tool, and re-enabled Windows Defender, which, it turns out, is very formidable. I've been saving a couple virus files that infected two of our clients that NOTHING would touch. I'll refer to it as the "super, secret, sexy, porn, password" virus. Diabolical little bug...basically had to find how to manually remove it at the time. Malwarebytes, SAS, TDSSKiller...nothing detected it.
Windows Defender picked it right up today.