Right, so we bought a new computer to be used for media stuff, nothing fancy just a bit faster than our old one. so we had our old computer that was working fine, bit slow, whatever; took it apart when we got the new computer to use the hard drive sound card and two disk drives. the computer UPSTAIRS (yes different computer) was about 5 years old and outdated and slow. so we thought we would upgrade it to the slow one from downstairs with hard drive and sound card from upstairs. once we had put everything in all the right sockets; it wouldnt turn on. not even a flicker. just nothing. so. we tried another power supply. still nothing. tried literally everything. NOTHING. so we gave up for a night. in the morning when we retried, did everything the exact same, and it turned on fine. so when put it back in the newer case, so it doesnt look old. and it no longer worked in the old case. so put it back in the one that it was working in. AND AGAIN IT DIDNT WORK. even though just before it was working in this case. everything looks fine. tried a working power supply (three different ones), tried taking things out, and still nothing. SO WHAT COULD THIS BE? as im a college student and have a lot of coursework which is needed . (and no i cant do it on the new computer. anything we could try would be appreciated. thanks, (sorrry for essay.) Chris.