E3600 RAM PROBLEM AND QUESTION

[PAINMAN69]

I have a E3600 Gateway Serial no. 0026638785 an I'm running it with window xp pro. Right now I'm running two 512mb and one 256mb rams, problem I'm having is when I replace the 256 with a 512 my computer halts on start up and tell me something about new hardware not installed properly. I've tried the 512 in other slots an it works fine, check bios on start up an it reads all three 512mb of ram but still halts start up, any idea how I can fix this?

Can you also end a conflict for me, I been told I can only run three 512mb of ram in this computer by 1 source and other source tells me I can run three 1024mb, which is right?

[xodusss]

Intel (El Paso) Motherboard - 1.6-GHz [Part #2516093]
The motherboard was designed to support 3 gigabytes (GB) of memory based on the 512 Mbit technology. However, this technology has not been validated on this motherboard. Gateway has qualified this board for a total of 1.5-GB system memory using 3 identical 512mb chips. Further support may be available on the Intel website.

Dynamic interface memory module (DIMM) features include:

* Three gold-plated 3.3 volt (V) un-buffered DIMM slots
* Support for SDRAM at 4-clock, 133-megahertz (MHz)/PC133 only
* Support for 64-megabit, 128-megabit, 256-megabit, or 512-megabit memory technologies
* Single or dual-sided un-buffered SDRAM DIMM configuration
* Suspend-to-RAM (ACPI S3) support.
* Serial Presence Detect (SPD) 1.x or later
* Support for type CL2 and CL3 devices