Critical Process Died

Hi

My son's Aspire laptop refuses to reboot Windows 8. He doesn't know what he was doing at the time of the orginial crash but I'm guessing he picked up a virus. McAfee Internet Security is installed and was running at the time. Tried system restore, refresh/revovery and reset but not one of these options work and I'm asked for a back-up/recovery disk (W8 was preloaded and no disks were supplied at the time of purchase). It's just a month out of warranty.

I eventually managed to get into Safe Mode and updated McAfee. I started a full,scan which stalled shortly after. All the signs point to a virus which may explain why system restore and factory reset are not responding. Before I hand it over to an expert to rebuild, is there anything I can do to get W8 back?