when I attempt to run a boot time scan, it can only complete approximately 6% and then powers off for a re-boot.
Maual download latest avast definitions and update mbam to most recent version.
Since you have long passed option of System Restore (I assume you have), you can turn that off.
Right click on My Computer-> Properties-> System Restore tab-> click on Turn off System Restore.
Unhook LAN. Boot into Safe Mode. Run mbam, resolve findings.
Set avast boot-time scan. Restart.
You should be able to run the scan right through. If not, try to note the folder / file locations that are running before and around the 6% point where the scan falters.