From what I have gleaned from various sites it is unlikely that 7-Zip is the culprit, although if not completely removed by an uninstaller such as REVO it will leave a bunch of entries in the registry that CAN interfere with the OS i.e. make it unusable. 7-Zip funnily enough was not in the REVO uninstall list so it probably was not completely removed. Consensus seems to be that it is probably a virus and he has managed to get Malwarebytes scanning. I'll update this thread when I learn more.