Originally Posted by chazwyman
I've got a late 2099 MacBook Pro.
Found your problem: 8GB of RAM is roughly 1000 times too small for the thing to even boot. Moore’s Law, man.
When I insert memory and try to switch the machine on all I get is 3 beeps pause 3 beeps pause....
You probably just seated it incorrectly. Open it back up and reseat the RAM.
If that’s not the problem, it’s also entirely possible the new RAM is faulty. You said kit, so I assume that’s two 4GB sticks. Drop one in with one of your old 1GB sticks and see how much RAM the computer reports. If only 1GB, that stick is faulty. Then test the other stick in the same way.