This may be more a simple case of memory creep or chip creep. Chip creep is the process of PC components creeping out of there expansion slot over time. This occurrence is directly caused by the heating and cooling of the ambient temp inside the PC case. As the temperature rises your components, and slots will expand, as the PC cools these same part shrink back down. The constant or frequent expanding and contracting inside your PC causes the "chips" to "creep" and become loose from there assigned slot.
Chip creep can effect all different components and part inside the PC, from hard drives, to PCI slot, and RAM. Even Molex connectors and drive cables can be effected by chip creep and loose solid connection to the hardware. So keep in mind before you throw it out the window or bash it with a hammer... just rebuild it first you may be surprised at what it can fix.
Or to put it another way: Potholes in the road occur in the same sort of way.
Edited by Neil Jones, 18 February 2010 - 07:45 AM.