How confusing can you get? HP sold three different models of Presario 5009.
Yours must be the one with the Athlon chip in it, because that is the only one
with 3 DIMM sockets.

The only possible explanations here a
1. The memory is just plain defective.
2. The memory has high density chips on it, rather than low density.
3. The memory does not conform to the motherboard specs in some other way, such
as it is registered not unregistered.

If you got the memory from a reputable source, I'll guess that the motherboard
requires low density memory, i.e. memory with more chips on it. Count the
chips. If the number of chips is not 16, you may not have the right memory
there... Ben Myers

On Tue, 27 Feb 2007 03:31:31 GMT, "Adman" wrote:

I am trying to install more memory on my Presario 5009. I have 3 128mb
SDRAM 100 memory sticks in the machine now. I purchased a 256mb SDRAM 100
to replace one of the 128 sticks. When I install the 256 stick the computer
will not boot, nor recognize the memory. The harddrive starts, but so
compaq spash screen. I've tried all sorts of combinations for seating the
memory, but nothing seems to work. When I put the 3 128 sticks back in
everything works fine again. I know the new memory is the right kind.

Any thoughts would be appreciated.
Thanks