PC133 SODIMM Upgrade

I am upgrading my Dell Latitude CPTx S500GT from 256MB RAM to 512MB, which is the max. I bought two Micron 256MB PC133 144-pin SODIMM sticks. The laptop calls for PC66 originally, but will (and has) underclocked PC100 and, I think, PC133 128MB sticks before.

The problem is, when I insert these two Micron 256MB sticks the laptop will not boot. In particular it will only run the memory test for 2-3 seconds before shutting back down. Obviously it is not seeing the new RAM, but it should. What else can I try? Any opinions on what is wrong will be appreciated.

My laptop system info is as follows:

OS Name Microsoft Windows XP Home Edition
Version 5.1.2600 Service Pack 1 Build 2600
OS Manufacturer Microsoft Corporation
System Manufacturer Dell Computer Corporation
System Model Latitude CPt S500GT
System Type X86-based PC
Processor x86 Family 6 Model 8 Stepping 3 GenuineIntel ~497 Mhz
BIOS Version/Date Dell Computer Corporation A16, 3/5/2003
SMBIOS Version 2.3
Windows Directory C:\WINDOWS
System Directory C:\WINDOWS\System32
Boot Device \Device\HarddiskVolume1
Locale United States
Hardware Abstraction Layer Version = "5.1.2600.1106 (xpsp1.020828-1920)"
Total Physical Memory 256.00 MB
Available Physical Memory 64.27 MB
Total Virtual Memory 874.07 MB
Available Virtual Memory 521.66 MB
Page File Space 618.66 MB
Page File C:\pagefile.sys

 

this is sort of happening with the memory that I purchased for my PC. I out both chips in and my computer restarts and restarts!

The memory manufacturer was no help!
HP was no help!

Hodo was of some assistance, but nothing that got the chips to work.

Is this the same situation thats happening to you with your computer and chips?!?!?!

 

No, it just doesn't see the memory on POST. It only powers up for about 3 seconds and then shuts back down.