Go here http://www.crucial.com/

Look for the scanner. It will scan your system and tell you what kind of memory you need. It is a start however a problem I ran into once was that the memory manufacturer said their memory was compatible and my mobo maker said it wasn't. Turns out the mobo maker was right. Have you called HP support and asked them?

 

Thanks, but I tried this already. Comes back with the following results - it thinks the MB has four slots, but I know it physicaly has 2.

* Maximum Memory Capacity: 4096 MB
* Currently Installed Memory: 1024 MB
* Available Memory Slots: 2
* Number of Banks: 4
* Dual Channel Support: N.A.
* CPU Manufacturer: GenuineIntel
* CPU Family: Intel(R) Pentium(R) 4 CPU 3.00GHz Model 3, Stepping 4
* CPU Speed: 3000 MHz

Then it quotes "Our System Scanner was able to find some of the data we need to make a recommendation, but we need more information to ensure a compatible match." But try to pick my system and it's not listed....

Last time I called HP, they were rubbish - premium rate number and I spoke to iddiots so not keen on that route.

 

https://www.techspot.com/vb/topic65114.html

 

Thanks for posting the URL link, but it doesnt really help.
You dont get a motherboard manual with a prebuilt PC. I tried contacting HP via online support, they could not answer....

Surely somebody knows!!! Oh well, just have to go with the more expensive chips just in case.

 

You have 2 banks used 1024MB, 2 banks free. Get 2 more sticks of exactly what you are using now. This will increase your memory to 2048, and you know the additional memory will be compatible...

You have Double Data Rate 400MHz memory now. These are your motherboard specs:

http://h10025.www1.hp.com/ewfrf/wc/genericDocument?lc=en&cc=us&docname=c00063272

Hi-Density RAM... No

 

thanks. Although regardless of what crutial memory report suggests, I only have two memory slots with are both populated.

I had found the page form HP, but I could not tell from that I could not use high density ram - so thanks for the steer. How could you tell?
Thanks again

 

Yes,
I was confused by that 4 slot information. If you want to go to 2GB's you'll have to buy 2 DDR 1024MB 400MHz sticks, AND REPLACE THE 2 STICKS YOU HAVE... No Hi-density! They will be expensive enough. YOUR MOTHERBOARD WILL NOT SUPPORT HIGH DENSITY RAM!