512MB RAM Stick problems

[OverlordoftheGalaxy]

I have 1 256MB SDRAM stick already in and is what my computer is running off now.

I have 2 512 SDRAM sticks that i want to put in, i have enough places to put the 2 sticks in but when i do the computer freezes when it's starting up (just after the reading of the memeory)

I have tried just having 1 old and 1 new. Just 2 new 1's Just 1 new 1 but nothing works.
( When trying the different combinations i often got as blue screen abit like the physical memory dump 1 come up)

Only having the 1 old 256MB stick works.

Can any 1 give me any advice on what to do about this and how to get it to work?
Thanks in advance from me ^^

[TazUk]

What type is the current memory and they new memory i.e. PC100, PC133, ECC, Registered, CAS 2, etc.

[OverlordoftheGalaxy]

the old 1 is a samsung PC133

and the new 1's are infinity PC133 ... both SDRAM DIMM too

thanks in advance somemore ^^

[TazUk]

Double sided or single sided?

What make/model of motherboard are you using?

[OverlordoftheGalaxy]

The new RAM's are single-sided

And my motherboard is :

'ASUS
CUSL2-C Motherboard
'

On the motherboard box it says:
3 x DIMM - Max.512MB PC133/PC100 SDRAM

(Has it happens i am trying to put in a 512MB PC133 SDRAM into it ^^, but i just dont know why it doesn't work.)

Thanks for your contribution so far ^-^
Thumbs up to you

[davey6]