IBM Aptiva Hardware Handbook page 52

Step 2
Did the system unit beep after it was turned on?
Yes, more than once
Yes, once
42 Problem solving steps
There is a problem with the system unit. Find the code in "Error codes,
descriptions, and corrective actions" on page 57, and take the action listed.
The system unit has passed the power-on self test (POST). Go to Step 3.
There is a problem with the system unit.
No
a. If you added hardware, remove it and restart the computer to see if the
problem is corrected. If the problem is corrected, you may have installed your
hardware incorrectly. Reinstall your hardware. For instructions on installing
hardware in your system unit, see "Working with your system unit" on page
81. For instructions on installing options on your system board, see "Working
with your system board" on page 103.
b. Check that memory modules are installed correctly. For instructions, see
"Working with your system board" on page 103.
If the problem continues, check your Services and Support Guide for information
on obtaining service.