The RAM must be paired, upper and lower. Work your way from inside to outside. Be sure the RAM is DDR 400 (PC3200) unbuffered.

This may be useful to you:

• 1 Flash: No RAM is installed or detected.

• 2 Flashes: Incompatible RAM types are installed.

• 3 Flashes: No RAM banks passed memory testing.

• 4 Flashes: No good boot images are detected in the boot ROM (and/or there is a bad sys config block).

• 5 Flashes: The processor is not usable.