I'd appreciate any help I can get with this one! I'm running Win10 64bit. About three months ago, my C: drive went into shock and wouldn't boot. I put in a new drive, reloaded windows, and was able to access most of the old drive and recover most of my material. But that's not really the problem, just the context.
Starting perhaps a week ago, my system has been badly behaved, to say the least. I use both Firefox and Chrome. Both of them have developed problems with hanging up, going to wrong pages, etc. Two days ago, I got this alarming popup saying that it was from Microsoft and if I didn't call this number right away, they would disable my computer. I hit the OFF button immediately and shut down the system. It came back up OK, so I did a system restore to about two weeks back; that also worked, presumably. But later that day, I had another similar popup. I repeated the procedure. But this time when it came back up I ran several varieties of malware scans - AdwCleaner, Hitman Pro, Malwarebytes Pro. Each of them found some instances of things to get rid of. Then I tried to run ESETOnline Scanner; this runs, but hangs up somewhere after saying that it's detected 4 threats. I've tried this several times, including in safe mode. I also tried to run TDSSKill rootkit finder. It wouldn't run in regular mode (got to some point and hung up - had to shut down the system to close it). But it did run in safe mode, and said I was clear.
I've also had a large number of Malwarebytes warnings that it wouldn't connect to some website - never the one I was trying to get to; something else. This is particularly disturbing.
At this point I'm really confused. I don't know what might be due to a problem with the system itself; what might be a problem with either or both of the browsers, or something else entirely.
Can you help me systematically figure out what's wrong? My approach of throwing things at it and hoping something will stick clearly isn't working.