I got it sorted, turns out i hadn't the modules seated properly. I was being too cautious when i put them in so the pins weren't making proper contact.
Thanks for yout help though, much appreciated.
I've recently upgraded my laptop from 512MB of RAM to 2G RAM and after installing the modules and attempting to start up my laptop nothing happens. The power light comes on, along with the caps lock, num lock and scroll lock lights and...