Yes, I have put 1 stick in slot 0 by itself. Same result. I have also tried it in slot 2. And also tried the other 1Gb stick on slot 0 by itself. I cannot find anything on the packaging with the K-Byte 1Gb DDR2 4200/3200 PC2-533/400 240 Pin sticks (or on K-Byte's web) that indicates that they are or are not unbufferred or non-ECC! Next step is to return the sticks to store and have them check them. Any other help will be great! Thanks. Mark -----Original Message----- From: Personal Computer Hardware discussion List [mailto:[log in to unmask]] On Behalf Of Paul Hachmeyer Sent: Friday, March 31, 2006 5:31 PM To: [log in to unmask] Subject: Re: [PCBUILD] RAM upgrade - 512Mb to 2Gb Did you try 1 stick in slot 0 by itself? Usually the slots are numbered. You may need to insert them into slots 0 and 2, skipping one slot. But I would try the single one first in slot 0. Is your memory unbuffered non-ECC? I'm having spontaneous reboots with an hp machine as well as other errors, but I'm using 1 gb DDR. Everything was fine until I added the 1 gb chip to the 3 x 512mb already installed. Specs from HP for your motherboard: * Dual-channel memory architecture * 4 x 240-pin DIMM sockets support unbuffered non-ECC 4 GB 533/400 MHZ DDR2 memory modules * Maximum HP/Compaq approved memory is 4 GB* Mark Lundy wrote: > I have an HP a1020n P4 3Ghz with 2 256Mb of DDR2/3200 PC2-333 sticks in it. > I replaced those with 2 1Gb DDR2/3200 PC2-533/400 sticks. The BIOS sees the > 2Gb. However, WinXP Home hangs during bootup, always at the point when the > blue bars are moving across mid-screen. WinXP will bootup in safe mode and > it does see the 2Gb of RAM. > I have made sure the BIOS is the latest version. I have installed only one > stick at a time. I have put the sticks in the other pair of slots on the > MB. WinXp always hangs during the same time at bootup! > Hope someone has some ideas. Thanks in advance. > Mark The NOSPIN Group is now offering Free PC Tech support at our newest website: http://freepctech.com PCBUILD maintains hundreds of useful files for download visit our download web page at: http://freepctech.com/downloads.shtml