happ......I wouldn't panic yet .....How long was the pc in storage for and where was it stored .......?
What operating system does it have on it ?
I would be inclined to disconnect all power to it , open it up , then carefully remove the ram , any pci cards .....at this time I would leave the processor and its heatsink alone......get yourself a can of air.....and blow out all the dust which may have built up as a result of the unit being in storage. Be sure to blow out the area where the processor and heat sink are very well ....( use a chopstick or some similar non metalic object to prevent the cpu cooling fan from spinning) . When you have things clean inside ......replace the ram ( being careful just to handle it on the ends ) and the vid card........dont worry about any other cards at this time.....Take a minute to be sure all the ide cables are plugged in and tight. ( If in doubt, unplug them and plug them back in ).....Now , plug the mouse , keyboard and monitor back in . You can leave the case open for this test ........now reconnect the power chord to the tower and try to start up .......( make sure the monitor is turned on ) record exactly what happens ......does the leds on the front of the case come on , does the cooling fan on the cpu start , does the cooling fan on the power supply start , Did the led on the floppy drive come on ....did the led(that indicates hard drive activity come on )and what beep or beeps do you hear .......
let us know .
dl65