You should be fine putting in any memory that you comes to hand. It doesn't seem to matter if the memory is a different speed, as long as it's compatible. There's a good website where you can enter the laptop details and it will tell you the type of memory that you need, and the maximum size of memory that you can fit in that machine - google for Crucial or Kingston for more info.
To add memory, it's easy provided that you take your time and do a little preparation.
Unplug the laptop and place it face down on a clean, level surface. The memory is generally found under the laptop, behind a little door, with a screw in it.
While doing the job, try and sit or stand still - rubbing your shoes on carpet or rubbing cloth can create static which can damage the components. Componentry is a lot better than it was, but you might as well play safe.
Undo the cover to gain access to the memory.
Take your time and have a look inside. You should take note of:
1) There is a little key in the socket, so you can only put the memory in one way round
2) There are clips at the end of each socket that you spring outwards to release the memory, should you need them.
3) Try and find an exposed piece of metal that looks like part of the laptop chassis, but NOT a connector.
Now look at the memory, which should be in an antistatic bag or container. You should be able to see the slot that matches the key - take note of this for later.
Open the packaging for the memory and then, with your fingers, touch the inside of the packaging and the metal area that you checked for above. You, the laptop and the memory are now at the same voltage, which minimises the risk of damage to laptop or memory.
Take hold of the memory by the short edges, and avoid touching the chips or the connector.
Slot the memory into the socket and then push it firmly in so that it's fully located. Finally, push down along the back edge of the memory stick and it should locate with a satisfying click. If it doesn't go in neatly, undo the clips, pull it back out, and try again.
Finally, pop the lid back on, power it up, check the memory in the BIOS and Robert's yer Mother's brother.
Edit - I see Judge has good taste in memory too.
It's a simple DIY job really - I'm just trying to teach you the best practice. Last time I had a laptop in bits, it was at a conference and I had all the bits on the table in front of me - the PC equivalent of a roadside engine strip, but a lot cleaner and quicker!
And just in case you don't believe me, Crucial have an
install guide with photos.
