I own a Carillon PC - Pentium 4, 3.2 GHZ - shipped with 1 gig RAM. I was having some performance limitations with my computer on a specific session that I was working on. When I was chacking the computers performance on task manager it seemed that I was maxing out on my RAM consumption. I went out and purchased another GIG of RAM (DDR - 400 MHZ), I previously had only one GIG of RAM. When I tried to install the RAM it was pretty tight and I had to undo one of the connectors right by the RAM and the HArd Drives. I installed the RAM and booted it up , everything worked fine. I was trying to get my Waves APA up and running so I had to boot up a few more times. I checked My Computer / Properties to make sure that the computer was recognising the RAM and it was. Next I fired up PT-LE and opened up the session that I was having the performance problems with. Interestingly enough the same performance problems seemed to persist. As I was busy trying to get the session to play the whole system shut off. I don't mean it booted itself down, the computer just shut off completely - black screen and all. When I tried to reboot it up the computer made a sound sort of like a police siren (high pitch, low pitch, high pitch , low pitch etc..) and then stopped. :roll: :shock: Any ideas on what may have caused the problem? What could/should I check? Could I have accidentally unplugged some wires during the RAM install . ANY help would be greatly appreciated, thanks.