Hi - my manual says that my system will run 512mb. I've just bought 2 new 256mb sticks to replace the existing 2 x 128 sticks. Whilst both the new ones work by themselves, the system will not boot up when I load them together. I've also tried 1 x 256 with 1 x 128, again nothing. Any ideas?? jph

You may have a bad number 2 slot....or your not getting the ram fully seated in the second slot. Sometimes it takes a pretty good push to seat the memory, especially if the slot has not been used. I am assumming the new ram is a matched set...meaning the same brand and type. If they are not the same brand and type....some motherboards will not except the second chip. Also you might go into your bios and make sure the ram settings are correct for the type of ram your using....some motherboards have a setting for ddr or sdram...and their could be some timing settings as well. If that all checks out.....I have a feeling it is your motherboard that is the problem.

Hi zero244. Chrecked out most of that. Both sticks were purchased yesterday. Both clip into position on the board, and both work indpendantly of the other, and both work in both slots, so stuggling with this. As I posted, even if I put in just one stick with one of the old ones, it still doesn't work. It does try and sort of boot up, but the must lingers! jph

Also some mobos have jumpers that must be changed when you change the amount of memory. Bob If you wake up to see the day - it can't be that bad.

Sorry to sound thick, where do I find the jumpers and how should I re-configure them? jph

Have a look in the manual, anything that you need to do will be in there. If you look towards the start of the book there should be a diagram showing all the jumpers etc, with a page number that explains their function.

Checked out the book, no jumpers. Checked the motherboard and again nothing. Whilst HP say my system can be upgraded to 512mb, is it possible that they put a lower capacity motherboard in the system and this is the problem. Is there anyway Ican tell? Cheers jph