Ok so recently my PC(custom built and i bought it) started running slow after a few minutes after startup.. Then suddenly it stops booting turning off and on constantly.. After removing the ram and placing in different slots it started to boot up but had the same "Running slow after few min problem".. At first i thought it was a Power Unit problem but to be sure went to a PC repair centre.. He said it is a VIRUS and that he has to backup,format and reinstall windows totalling upto 70$.. Can a virus do that or is he trying to loot me? Thanks in Advance