Last night I turned on the Power Mac 5200/75 LC, it has an ethernet card, video in, TV in and a 25-pin SCSI terminater atached if it matters. Well I turn it on and starts to boot it, it gets to the Mac OS screen (I am running Mac OS 8, I think) and says "Starting up" Well a few extentions if any begin to load and the Mac suddenly shuts off with no warning. So then I flip the On/Off switch from On to Off and then back to On. I press teh startup key on the keyboard and it Starts up fine. I watch TV on it for about 1 to 2 hours and then I shut it down. Today I went to turn my Mac on and it did the same thing, it started to load and then shut off. This time I flipped the switch again and kept hiting the startup key. Still nothing happens. I turn the power strip it is connected to off and on. Then I pressed teh startup key on the keyboard and it began to startup but then shut off agian. Now I cannot get this machine to budge. it won't turn on no matter what. I read the Apple Service manual and it didn't say anything about unexpected shutdowns. One of you said in the IRC chat that it might be the PRAM. If it is then I can get a replacement for about $13 so it is no problem. I thought the problem was the Power Supply but then maybe I am wrong. I have installed the Video In and TV Tuner card on this Mac so I supose the PRAM battery would be simple too. I hope it is on the same board, I don't want to go anywhere near the CRT. Can anyone confirm that the probelm is the PRAM? This would be most helpful...