First, don't assume immediately that it is that, or that they actually did that. I realize what I just said too.
Second, call upon me, or another experienced sysadmin here to take a look through your machine via teamviewer, while you watch obviously, and;
Third, Download and install ESET Nod32 Antivirus and run a complete custom scan on C:\
note: I do not accept money for helping out if that's one of your questions.
Lastly, relax, it is most likely a false assumption, however, it's good to be safe of course. You know how to contact me.