major RAM probs!

(Win 2000 pro SP2, Pentium4 1.3Ghz)

I currently have 128MB of RAM and despretly need more as I have broadband internet and like to listen to music, use p2p programs, play games etc

I want to buy more and try to install it myself.

I know I need:

RIMM (RAMBUS), PC800, 400Mhz or better, width: 16bit

My slots are:

1: 64MB

2: 64MB

3: -

4: -

I look on Ebay and I see stuff like:

256MB Rambus RIMM PC800 ECC Memory 800-45

RDRAM 1GB pc800-40 Rambus

What the hell does ECC mean and how do I know if mine is 40 or 45? And how do I know if it's 184 or 232 pin? Everest Home edition never told me that?

And do RIMMs need to be installed in pairs? ie if I wanted to add more would I have to populate slots 3 and 4 with the same capacity module?

Thanks :)

Please see these two topics:

http://forum.ccleaner.com/index.php?showto...3229&hl=crucial

http://forum.ccleaner.com/index.php?showto...1390&hl=crucial