Memory

To test system sub-system memory for defects, I recommend Memtestr86+. Memtest86+ is a port of the popular original Memtest86, developed by members of the x86 secret team. Just like it’s parent it’s OS neutral.

You need either a blank CD or floppy disk For floppy disk, download the latest Pre-Compiled package for floppy DOS/Windows and use the raw write utility to create a Memtest86+ boot floppy (This link should take you straight to the download section). Reboot and ensure your BIOS is configured to boot CD/Floppy before your primary HDD, then allow Memtest86 to load. Allow it to complete at least one pass.

You are aiming for zero errors, but false positives occur occasionally - especially on low quality motherboards. If you get errors, try rebooting and trying again. If it continues, you most probably have defective RAM.

Note that although Memory diagnostic utilities are aiming to test RAM, a failure may not point directly at RAM but to other components involved, such as the CPU, memory controller (excluding Athlon 64s) and other motherboard components. Overclocking and tight memory latencies can also cause errors.

Windows Vista ships with it's own Memory Diagnostics Tool, located in Administrative tools. Much simpler to use, you simply run the applet and opt to reboot now or later. Next time Windows starts up, the memory test will be run. Results are displayed when you next log on.

Hard Disk Drives

Most HDD manufacturers have developed and maintain their own diagnostic utilities. If you know the manufacturer of your HDD you can find a link to appropriate utility in the following list.

Seagate – SeaTools Desktop
IBM/Hitcachi - Drive Fitness Test
Maxtor/Quantum - PowerMax
Western Digital – DLG Diagnostic
Fujitus – Diagnostic Tool
Samsung - SHDIAG

If you’re lost, or your manufacturer doesn’t appear here, SeaTools Desktop has a generic (but slow) test that will work on any drive.

Ultimate Boot CD

Rolling nearly every staple diagnostic utility into a single ISO, Ultimate Boot CD (UBCD) is a free if slightly heavier download. If your connection isn't up to it, UBCD can be obtained for very minimal costs in many different locations.