Infected .sys and .dll files, access denied?

I just finished digging my PC out of a whole mess of malware, most of which was taken care of by MBAM; I suspect it was some strain of Vundo. At any rate, now that the bulk of the problem is resolved, I still have a few issues -- primarily, two specific files that continue to register as Trojans with AVG. I can't access them to heal or to quarantine, and I'm uncertain as to whether they're legit system files or not. The files are afDg51.dll (in %sysroot%\sys32) and tdxjs.sys (in %sysroot%\sys32\drivers).

Help a sister out?

Thanks,
Cassandra