Apple says 'Please connect the mouse to a USB keyboard.' Note that the Apple Hardware Test cannot be used when a mouse is directly connected to the USB port on the display or on the iBook. On other Macs, a hardware test can be performed by inserting the Mac OS X Install CD and holding down the 'D' key while the system is starting up. To use the Apple Hardware Test CD, restart your computer while holding down the C key until the 'Loading.' icon appears. You can sometimes determine if you have a 'bad' RAM module by using the Apple Hardware Diagnostic CD, included with all currently shipping Macintosh models. If you have kernel panics that don't seem to be specific to any device, application or intensive CPU activity, you may have bad RAM.

Problematic RAM modules constitute a primary cause of kernel panics that occur in a seemingly random fashion. As with many other Mac OS X troubleshooting techniques, its often easier to throw multiple relatively harmless solutions at the problem of repeated panics in the hopes that one or more will stick. The kernel's interaction (direct or indirect) with virtually every application, connected device, processor, software cache, and network service, however make its crash suspects a broad bunch. The hardware/software communication duty is part of the reason so many periphery devices and RAM issues are implicated in kernel panics since the kernel handles how programs are loaded into memory, and how applications call and respond to external devices (among other duties) a loose RAM module or a FireWire hard drive with bad firmware can throw the kernel for a fatal loop. When a kernel crash occurs, the system generally cannot recover without a restart of the kernel - requiring a full restart in Mac OS X. It's a dead-end hang for the kernel - the crucial center of Mac OS X that handles various aspects of hardware/software interaction and system calls. What exactly is a kernel panic?: Basically, this is one of the lowest level crashes that Mac OS X can experience.

Cnet mac memory cleaner