Windows only shows 256 out of 1.5 gigs of ram

I have dell dimension 4600 P4 2.8 and 1.5 gigs of ram. PC came with 512(2x256) of ram and later i added 2 more sticks of 512 Dual Kingstone ram. Everything was working fine untill my HDD burned i bought a new HDD and instulled it it was givving me hard time so i flashed the bios and evrything was fine. Now i dicovered my pc is running slower and that Windows XP only recognizes 256 out of my 1.5 wich was working fine before, i switched the ram places and no matter wat i do even if i leave just one 512 stick in my pc windows still only see 256, but in the bios it say 1536 so i dont think its a problem with the bios they show evreything fine weather i put in 256 1 gig or 512 the bios show the right amount but windows always shows 256. Can anyone plsea help me!!!!!!!!!!!!!!!!!!

 

Yea i tought of that but why would there be a problem with the bios if they show the correct amount of ram all the time 256, 512 1gig or 1.5 they bios show the right amount all the time

 

but how do i flash back to the bios i had??

 

thanks, i will try that when i come back from work and post my results.

 

I cant belive it lol i flashed back to a previous verison and it didnt help, but i am not sure what version i had before maybe it is even earlier one

 

Can you show us a screenshot of your system properties?

Right click on my computer, choose properties.

Make sure you blank out any product ID or other information regarding yourself.

 

I currently have 2x512 inserted but still shows 256

 

Ok, go to start, run, and type C:\boot.ini.

Copy its contents to here.

For example, here is mine:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /usepmtimer

 

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home Edition" /noexecute=optin /fastdetect

 

Try this:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home Edition" /noexecute=optin /fastdetect /maxmem=1536

 

You will need to reboot with those changes.

 

i did but still shows 256 nad rebooted

 

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home Edition" /noexecute=optin /fastdetect/maxmem=1536

 

Does all of the ram show up in Safe Mode?

 

I have also tryed goin to run, msconfig then boot.ini and the advance options i couldnt chnage the maxmem there higher then 255 before, but once i did what u have told me i went in there just to see and it was 1536 but once i pressed ok it switched back to 255 automaticly

 

Safe mode shows 256, but the boot.ini file is still set to 1536

 

messing around in the system setup i fixed my error, i just turned off the OS setup mode or something like that in the bios thats wat was limiting my memory in windows. Thanks alot for evryones time and effort