Thank you very mych for your help!
Luckily my problem was a false positive.
I run OTL to clean up, but Codechek and JRT are still on my desktop. I guess I can remove them manually?
Just two questions:
1) Regarding the cache that Firefox seems not to clean properly, as you explained:
would the Disk Cleanup utility (also described in the post you referred me to in your last post) delete the cache completely in the same way you did with OTL? I use this utility every month or so, so I was surprised by the large amount of MB that you removed from my cache. If Disk Cleanup does not quite do this properly, could I use OTL the way you have done? Or is there something else similar which can do the same job?
2) I have never had a false positive issue until this time. If it ever happens again and Avast quarantines a file and I see that any scans I run give no issues, can I still come back to this forum or should I go elsewhere?
I appreciate the help you guys give, so I wouldn't want to take your time as it seems there are people here with rather bigger issues, judging by the number of posts in other users' topics.