Need help after memory upgrade

[Roadking683]

Running HP pavillion with a supposed 512M memory
capacity. But if I put in 2 256M sticks windows will not
start in normal or safe mode. It justs keeps looping back
to a screen that apologizes for a problem starting and
restarts again. It works ok if I only put in 1 stick of
256 and 1 of 128. Any help would be appreciated.

 

[Alex Nichol]

Running HP pavillion with a supposed 512M memory
capacity. But if I put in 2 256M sticks windows will not
start in normal or safe mode. It justs keeps looping back
to a screen that apologizes for a problem starting and
restarts again. It works ok if I only put in 1 stick of
256 and 1 of 128. Any help would be appreciated

Some motherboards and chipsets rebel against particular combinations of
memory modules, and do not always take combinations that you might
expect. That may be one that will take 512 but *only* if in a single
module. Best advice is probably to use the 256 + 128 that works - it is
not a bad amount to be using