HP XW3400 - Manual (Page 159)

Power LED flashes Red five times, once every second, followed by a two second pause, and the workstation
beeps five times. (Beeps stop after fifth iteration but LEDs continue flashing.)
Cause Solution
Memory is installed incorrectly or is bad. 1 . Reseat DIMMs. Power on the system.
2 . Replace DIMMs one at a time to isolate the faulty module.
3 . Replace third-party memory with HP memory.
4 . Replace the system board.
Table D-13 Solving Memory Problems (continued)
ENWW Solving memory problems 149