Repairing and Upgrading Your PC

Troubleshooting Memory Installation and Operation

As electronic devices with no moving parts, memory modules seldom malfunction—if they are installed properly. When problems do occur, they may be as obvious as a failed RAM check at boot or as subtle as a few corrupted bits in a datafile. The usual symptom of memory problems is that Windows displays the Blue Screen of Death. Sadly, there are so many other possible causes of a BSOD that it's of little use as a diagnostic aid.

When Bad Memory Turns Good

As odd as it sounds, faulty memory is seldom the cause of memory problems. When you experience memory errors, the most likely cause is a marginal, failing, or overloaded power supply. The next most likely cause is system overheating. In particular, if the system works normally when first turned on but develops problems after it's been running for a while, power supply or heat problems are the most likely cause. Only after you have eliminated these possibilities should you consider the possibility that the memory itself is defective.

As a first step in diagnosing memory problems, run Memtest86 (http://www.memtest86.com). Memtest86 is available as executables for DOS, Windows, and Linux, but the most useful form is the bootable ISO image, which can load even on a system with memory problems so severe that Windows or Linux cannot load and run. If you have a Knoppix disk handy, insert that, power up the system, type memtest at the boot prompt, and press Enter. However you get it running, ...