I apologise about posting in two places. I didn't know whether it was COMPLETELY silly to think/imagine a virus could cause a computer to manifest what appear to be hardware problems (so silly that people might not reply). I don't know what hackers DO or what they CAN do if Malware has been placed on your machine. I didn't know if it is possible for someone to FREEZE your system and then muck you about in various ways. I rather assumed they could do ANYTHING.
When my boot-up finger-print reader wouldn't work I wondered if it had been disabled by someone who was trying to use a key-logger to obtain the machine's password. I didn't know if my lack of knowledge was making me OVERLY (and inappropriately) suspicious. I wasn't sure whether the warnings that Avast gave me were false positives or HIGHLY PERTINENT. It's confusing if you are distracted by not knowing when a red herring IS a red herring and what you SHOULD be paying the most attention to.
I have run my ThinkPad's "Rescue and Recovery" diagnostic tool in full now and it said the drive had failed three of four SMART tests. I have taken my confusion to the Lenovo Community Forum as I have no idea how to re-build a system that came with no discs.
I have a nasty feeling I was supposed to create Recovery DVDs while I could still get into Windows and that the option to make them is, ironically, NOT available in the Rescue area - even if the files are still all there and the diagnostics facility allows you to test CDs and DVDs !