|Thank you for your PM. I generally prefer to work on the forum.|
The way I read the original post I would have thought it quite likely that the 800 number your rang was some sort of scam. Not being able to post something on facebook could be for a variety of relatively simple reasons. The last one that would come into my mind is a virus.
What worries me more is whether allowing someone unknown to access your computer could have given them the opportunity to do something nasty to it in order to make money. For this reason it would be worth following the advice already given in #5 (from Safe Mode). If, as it seems, you are having difficulties with this, then at least download and run MalwareBytes free version to see if it unearths something. See third link in post #5.
I feel inclined to suggest putting the XP Repair on the back burner for now, unless you get some other symptoms that point more strongly to a virus.
Always pop back and let us know the outcome - thanks