After running a system scan earlier today, I found that my computer had been infected by a trojan horse. My reason for running the scan was because Windows kept shutting down and then recovering.
After calling Microsoft tech support, the diagnostics tech accessed my computer via remote session and discovered that I had been "cracked" (hacked) by someone with a foreign (non-U.S.) IP address.
A repair tech later fixed my computer--deleted files, installed a proper firewall, etc.
I'm nevertheless very scared that this had been going on without my knowing. From what the dx tech had found, access to my computer had been successfully established something like 18 times, and after speaking with him on the phone, he seemed positive that someone has indeed been watching my online activity or utilizing my computer (the latter is what really scares me).
Additionally, I couldn't really get straightforward answers to the questions of how long this had been occurring and what it could mean for my own safety (perhaps they simply didn't know?); in fact, I wasn't really getting many straightforward answers about anything. I remain worried because I've heard such horrible stories about victims of "cracking" who have had their identities stolen, had illegal files stored on their computers, etc.
So now for my questions: what sort of consequences can something like this have for me and/or my system in the future, and what, if anything, can be done to minimize or correct those problems? Is there any sort of entity I should be reporting this to (i.e. credit card companies)? If a hacker did put harmful material on my computer, is there any way it could survive a professional system clean-up? Could I be completely overblowing all of this and acting like a total paranoiac? Am I asking questions that no one can really answer?
Even though I've been assured that this problem has been eliminated, I'm still feeling panicked about any problems that could still arise from this. Any input would be greatly appreciated--thanks.
UPDATE: It seems that, merely six hours after Microsoft tech support supposedly fixed my computer and installed Hitmanpro (which I've been unable to find anywhere on my computer), it appears to be infected by another trojan horse (trojan.agent/svchost.exe). According to Malwarebytes, this has been quarantined--do I trust it?