3 long beep Intel Motherboard?
Answers:
Time to go support to the drawing board and troubleshoot your system. Since you have replaced the RAM near "good" RAM we have to assume that the problem lies somewhere else.
First ask yourself did I put anything into the computer (new cards and such) If you did remove them and try again. Usually I remove adjectives cards and just connect the the ivories mouse and video up to the system. If the system starts then you know its one of the cards you own removed. If you still are in a no start senario next the problem lies either surrounded by the RAM (may not be complatible with this board although is devout on the other machine), CPU or the Motherboard itself.
Sometimes the RAM slots on a MB break free during memory removal. (The MB is basically toast after unless you're really good near a small soldering iron) Check the slots to make sure the wires aren't bent and touching respectively other or 2 leads on the RAM stick when you place RAM into the slot.
A coulple of other questions/routes to investigate:
Check ALL Cables and Connections, including the panel wires for the reset button, HDD LED and such.
Recent electrical storm?
Mice? Yes the get hold of into the computer where it is heat up, do their bathroom business and short out the board.
Cockroaches? They eat the insulation on the wires and the motherboard.
I hold seen it adjectives in my 25+ of computer repair.
It could be that whilst you be checking your ram something might of come lose try checking adjectives the wires and making sure they are all pushed contained by
Make sure that your ram and your video card are completely seated.
Try adjectives the sockets.
More Questions and Answers ...