Drive has reported a fatal error to Disk Utility, HELP ME PLEASE!!!

Question

I'm a little worried my Macbook Pro has become an overpriced paperweight.
Here's what happened:
I had a spare 512MB RAM, which was taken out of my 24" iMac Intel Core 2 Duo when I replced it with a 1GB RAM and, after checking several sources on the web, successfully installed the extra RAM in the MBP.
I restarted the MBP and the new RAM was registered after checking in About this Mac. I then began using the MBP as normal and wrote and saved a Word document. I clicked on the email and Safari icons in the dock and they just kept bouncing in the dock without launching. Pressed Power button - nothing. Took out the battery and replaced it after 30secs and pressed power button. All I got was the grey screen with the Apple logo and the winding circle which stayed like that for 20 minutes.
First reaction was to remove the RAM and restart. Same endless grey screen and winding circle.
Rebooted from CD, checked disk and repaired and said everything was OK. Restarted without CD still nothing.
Tried Archive and Install and came back with an error during installation.
Tried Erase and Install - same error.
Tried to select startup disk and it no longer could find my HD yet Disk Utility could find it and told me everything was OK. Tried resetting PRAM nothing.
Tried to erase the HD and nothing happened. Erasing a HD takes some time, but everytime I hit erase 10 seconds later it was back to the same point where I began
Next tried to create one single partition and struck the message Drive has reported a fatal hardware error to disk utility. Even the lettering for the main drive is now in red.
Do I need to replace the hard drive altogether or is there a solution to this problem. Was it the RAM that brought me undone or was that just a coincidence?
PLEASE HELP ME!!!

Answer 1

make sure that you haven't used it yet as RAM can only be used in one machine, not transferred to another one (like you did).
Sorry, but that's completely untrue, and I don't know where you might have read or heard such a fallacy. RAM has no registration that even tells a system that it's been used, much less a key that would make it work only in one system. As long as the RAM is properly compatible and precautions are taken not to shock a system with static electricity while removing or inserting the component or causing mechanical damage, a RAM module can be swapped between systems as often as desired.