So my computers been running super slow the last couple weeks.  I've been running a spybot detection program along with bitdefender many times, but no luck.  They come back clean.  Finally after scanning for 26 hours Sat and this morning it came up with 2 viruses, but could only remove 1.  The scan said it could not remove the 2nd virus and to contact bitdefender.  I also scanned and logged with HijackThis, but again no results?  Anyone got any ideas.  
Thanks,
Dan