MY ze5460 wont see 1 gig memory?

I have the above mentioned HP notebook pc with 2 sticks of 256mb ddr pc2100 ram memory. I purchased a stick of PNY 1 gig ddr pc2700 backward compatable to pc2100 and pc1600 or 333mhz, 266mhz, 200mhz clock speed on mem.
Now no matter what configuration,
slot1 i gig
slot2 256

slot 1 1 gig
slot 2 empty

slot 1 empty or with 256
slot 2 1 gig

with the above configs, the computer only shows the 256mb stick

If I install the 1 gig ALONE, nothing happens, no video, no bootup

It's a HP ZE5460US with 2.53gHz cpu running Win2KPRO. Confirmed not seeing with "my computer" "properties" and with Belarc advisor. BIOS Does not see it either. Computer according to HP site says this should be ok up to 1 gig of ram what gives

 

Your computer's dimm is limited to 512 MB. Some old DDR ram based motherboards are liek this. so you can't put 1 gig in the slot

 

Or there are couple of other possible thing that happened

1. Ram is dead
2. You didn't place it correctly
3. BIOS is outdated

 

VIZEL..... Each of the 2 ram SLOTS limited to 512 mb? That could explaine it

1) I was thinking it's dead, but if 512 limit, moot point
2) I sure I installed it correctly, hehe 6-8 times
3)HP shows NO bios updates for this beast

I purchased it from a major electronics dept store and they had nothing under 1 gig..........pretty good how the world kinda forces you to upate

Thank You for the info..........Bruce

 

Ps...........merry Christmas

 

Would something like this work in my machine?

http://cgi.ebay.com/512MB-PC2100-26...ryZ80201QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Or rather asked another way......just about any 512mb ddr sodimm 200pin pc2100 or pc2700 backward compat to pc2100?????