An older motherboard vs. ram problem

Hi people,
I've run into some problems with installing
a ram module. If you have time to take a look
at the specifics and shed some light I will
be grateful.

The problem is with installing 1GB of RAM
into a PC based on Abit's IS7-V motherboard.
Processor is: Intel Celeron @ 2400Mhz,
Graphic Card is: nVIDIA GeForce4 MX 440
Ram is: 2x 256 MB PC3200 Kingmax (2 different modules)
OS is WinXP SP2
The new module is 1GB PC3200 Kingmax.

The motherboard has 2 ram slots, and the info
about compatible ram is vague, it just says
it supports 2 184-pin DDR modules each from
128MB to 1GB in size.

I tried to install the new module in almost
every combination with the old modules and
with 2 different versions of
Bios: 1.2 and 1.6 (the latest version),
and with various Bios settings
for latency and shadowing.
Nothing works and the behaviour of the
system is totally chaotic.

Few examples follow...
When starting windows in safe mode (latest bios, old
and new module), the startup freezes while loading
the AGP driver.
With old Bios I installed the new module
with one of the old ones and everything
worked fine, but after couple of restarts
windows started with disk checking
(wich often blocked) at startup.
With the latest Bios I inserted just the new
module and Windows freezes at logon. After the
restart, bios won't start, no display at all.
Even the two of the old modules have to be
put in the slots in an exact order for the
system to work (with the old bios).


So, if you know what might help, shoot.

Thank you for your help