Choosing a Memory upgrade

Hi , i have a little problem here , i want to upgrade my pc with more memory but i dont no which one is the best or the correct one...

my pc conf is:

Vaio 1.30GHz Celeron
256mb PC-133 SDRAM

the problem is that there are many kinds of memorys and i dont know which one buy ... like i dont know if a DRR would be correct, i even know what is DRR o DRR2 also there ara another kind like the ones that have PC5300 PC2700 PC3200... i want to upgrade my pc with 512mb so ... i have a little troubles here....

Go here: Crucial Memory Advisor™ Tool . ;)

WOOW! tnks!

You won't be able to install DDR memory sticks in your current motherboard, you will need to upgrade that too. Which means you will probably have to upgrade your CPU too.