Harvey Eastep Claimed to know how to make sure my system was safe! Reno, Nevada

I'm a 60 y/o man who trusted Harvey Eastep a neighbor  to check and make my computer more efficient.  My regular Computer Tech before leaving for greener pastures had put Windows 7 in and for the past months having Charter Communication I had a fast and legitimate system.  Not bad for a disabled man making less than $800 a month! 
So when he made the offer I took him at his word and for 45 mins I let him on my system while I watched T.V.!  Yes stupid but having faith is not the same as stupid!
Now Mozilla and IE both won't load facebook through my system that for some reason my legitimate W-7 or XP!! 
Now I've not been on any site that can would generate a virus and the trouble began immediately after he left!  
The following day I had him over and in my room and he knew I couldn't hurt him but let him know I knew and if anything happens I have his name and picture!   I only wish there was a insert photo here so that I can print and leave on his door but guess this will suffice!   TY