Does Not Boot - Fan Makes LOUD Noise

This started last week. It would freeze after booting within a couple of minutes. Now when I try and boot it blinks the white power on button light 3 times and the fan runs very very loud. It does not even try to boot. I have held the power button on until I get the loud tone and the rapid blinking light on the front and while this enabled a full boot the first few times it will no longer boot. I have removed the pram battery and left it out for 5 minutes, while the battery was out I held down the cuda switch for at least one minute. I have reassembled and the problem persist. Running Mac OS X 10.4.11. 2GB Ram (installed for at least 12 months and has caused no problems) 250GB 7200 rpm SATA HD. I use this Mac to run Classic as I have some legacy PPC applications (PhotoShop 4, SoundEdit16, How Many Days and a few others that I really really like. Is my Mac DOA? Can it be resurrected? NOTE: I have been using Apple since the late 80's and for a time worked full time for an Apple Reseller as a tech but that was back when the Blue&White Towers were king, the G3 iMac was just released and G4's were just starting to make their appearance, the heady old days of Mac OS 8. Currently I use Intel C2D iMacs (Leopard 10.5.7 [don't like 10.5.8] or Snow Leopard 10.6.7- depending on what I'm doing or where I want to plug my iPhone4 in) for all but the Classic applications. Is it time to move on to OSX applications or is there still life left in my old PPC G5 iMac? Thanks.