When I go to my computer and look at system info it shows I only have 512 memory but I have 1.5gigs of memory installed. It used to all show up but now it doesn't. ( ddr 2700 three sticks 512 each) This memory shows up in bios but no where else.I'm running xp pro.I have a gigabyte board with 3000+ sepron processor.

Any hardware changes from when it showed till now that it doesn't?

You are certain that the BIOS POST counts 1.5?

What shows in the Task Manager under Performance | Physical Memory?

I changed the case and the dvd drive.(From one plextor 716a to another same model just a different face)
According to pc pitstop the bios shows 1.5 gigs
Task manager shows 1,536.00 mb total physical memory

So the Task Manager sees all. 2 more scans to verify:
Belarc:
http://www.belarc.com/free_download.html
Everest:
http://www.lavalys.com/products/over...ng=en&pageid=1

This could be a cosmetic issue with the My Computer screen. The following should reset it:

Start - Run - MSCONFIG.
Go to the BOOT.INI tab and click on the Advanced Options button.


If there is a checkmark on the /MAXMEM= line then clear the quantity field on that line and also click on the checkbox to clear it.


Click on Apply and OK as needed to exit.


Reboot to put the changes into effect.

I went msconfig and there was nothing in the field and the box wasn't checked in maxmem. I down loaded new bios and that changed nothing either.

belarc
512 mb installed memory
slot 'ao' 512mb
slot 'a1' empty
slot has 1024 mb

lavalys
physical memory
total 511
used 333
free 177
utilization 65%

Are all 3 sticks identical? Strange how Belarc has that 1024. Also as the Task Manager sees it

Did you look at Lavalys under SPD?

Just as a test you could rearrange the sticks in the slots.

Hi already tried that I changed the arrangement and windows wouldn't start so I put it back and now it say's 1024 and no all three stixs are not the same brand.
belarc
slot 'ao' 512mb
slot 'a1' empty
slot has 512mb
1024 megabytes installed memory

Could be that one stick is bad? Is that the different brand? Or are all 3 different?

Have you run MemTest?

http://www.memtest86.com/

All 3 stixs are different ( I had to ebay this computer together as I could afford it) But they all showed up till recently.No I haven't ran a memory test I don't know how.