This PC was built yesterday, it is the first I've built, it has 3x2GB of DDR3. Today, while installing a new driver, it crashed to a blue crash dump screen and restarted, after which I checked the Windows 7 system information and saw that only 4GB of memory was detected. I checked the BIOS: only 4GB detected there aswell. I assumed that one of the 3 DIMMs had failed and decided to identify the faulty one by booting with a single DIMM, each in turn. After shutting down, I removed the power cable from the back of the case and as the room I was in is carpeted, touched my foot to a radiator before opening the side of the case. When I touched the case with my foot still in contact with the radiator I felt a very slight electric current in my hand. This didn't feel like static and the phenomenon persisted until I grounded the system by replacing the power cable. After this I (thankfully) could not recreate the electric shock whether the PSU was connected to mains or not. Perhaps unwisely, I rebooted the computer and much to my surprise I found that the full 6GB of memory was once again recognised. So what I'd like to know is what may cause the case to be electrified when the PSU is not connected to the mains, is tha even possible? And whether this may be related to the problem I experienced with the memory? I haven't turned on the computer since so I don't know if any of this is recurring. I can give more details of the hardware components if anyone wants to know. Thanks in advance to anyone might be able to shed some light on what just went on here.
In all likelihood, the RAM wasn't seated properly originally or there was something in the slot (dust, debris, etc.) that caused the RAM to make a bad contact. The shock was likely latent static electricity. Bare metal is much more effective at dispelling static electricity.
Very odd. I can only imagine that the mobo was making some sort of contact with the case. This could be very problematic later and I would check all physical contacts with the case one more time. Standoffs are very important when mounting the mobo and the mobo needs to literally hover over the back. The I/O panel may be an issue and I would check that as well. If all else fails pull it all apart and reseat everything. Beyond that its a weird one to resolve.
Cheers for the replies, guys. When I get some time I'll go over the insides and check for any bad contacts. Quick question, wouldn't latent static discharge all at once? Because this is more of a tingling which persists for as long as you touch the case (or at least for as long as I touched the case which was about 2 seconds). I shouldn't have said shock earlier as that makes it sound like you get a shock.
it still could be a connection between the mb and the case, as there are quite impressive capacitors present in a psu, who can keep a lot of power (watch the little light on the mobo, it only fades out twenty seconds after the plug is pulled). this power could be leaking to your case causing you to feel current when you're grounded. of course this effect goes away when the case is grounded (trough the mains; as you said). the ram issue is likely unrelated. hope this helps
I've had a chance to give the inside of the case a look over and apart from one half of the motherboard EATX 12v connection not sitting snugly in the slot I didn't spot anything that was obviously wrong. Standoffs are all installed so there doesn't seem to be any case/motherboard contact. Could there be a fault with the PSU or how I installed it?
Alpaca's explanation is the most likely (residual charge from PSU capacitors) - as to how it reached your case, try checking that any unused power connectors (Molex in particular) are tied up so they can't make contact accidentally.