What are the filenames of these HKLM files and where are they located?
AVG has a horrible scanning engine. My experience with it has been mediocre at best. There could be some malware in your computer that is causing it to slow down as well. Malwarebtyes is a pretty good tool (and free) to scan and clean for malware. I'd start from there.
Malwarebytes - www.malwarebytes.org