What kind of virus/spyware/adware programs are you running and have you scanned with then since this happened? Also, do you use a file cleaner like Window Washer or CCleaner?
Anti-virus and firewall software will do this. More RAM might fix it, we had to remove our firewall and anti-virus software from an older system. I've heard of this happening on newer/faster boxes also. Remove them, reboot, see if problem is solved, try another vendors solution.
I have scanned with Spybot, Microsoft Defender, MS Anti-Spyware and LavaSoft Ad Aware SE and removed all the files they found. But still have the problem.
I have used CCleaner before, but not lately. I'll try that and Window Washer. Thanx