All computers suffer to a degree from dust build up but in all the cases I have come across it only ever causes overheating by clogging up the cooler fins. Dust is not conductive unless it has particles of metal in it which is extremely rare. I did notice on your temp readout that it had a Max temp recorded above 80ºC, that is getting quite high, has your CPU cooler been cleaned recently. Has it been removed and then refitted without replacing the thermal paste? What temperatures do you see when games are played? To display the temps in your toolbar follow this. From the programs list open Core Temp, under Options select Settings, under the Display tab check the box next to "Close to System Tray" then click on Apply and close the GUI. That should constantly show your core temperatures in the bottom righ hand corner in the tool bar. You may have to click on the small arrow to customize the display to show the temps. A bad contact on the RAM modules is usually due to the contacts oxidising, a simple clean with a rubber cures the problem. Obviously if there is some dust or fluff in the socket prior to the stick being fitted this would cause a problem, but this would probably create an immediate and constant fault rather than a random one.