7E STOP errors: There are numerous individual causes for this problem, including hardware incompatibility, a faulty device driver or system service, or some software issues.
As for Memtest, I hope you ran Memtest86+, version 4.00, http://www.memtest.org/#downiso
. Older versions have been known to be subject to error, questioning the reliability of using such.
When testing RAM, any errors at all indicate a problem. The hard work comes in trying to determine just why the problem appears...it's not as simple as writing a given module off.
FWIW: Icrontic » Diagnose with Memtest86+ - http://icrontic.com/articles/diagnose_with_memtest86
The fact that you think you had a malware situation...is confusing. BSODs occur every day and they are not necessarily caused by malware...but they can be attributed to malware or hardware or software or O/S problems (depends on situation).