Asus Motherboard: P7P55D-E ProIntel CPU: Core i5-750 Quad-Core Desktop LGA1156BFG Tech Video Card: Nvidia GeForce 9800 GT 512 MBPower Supply: Thermaltake TR2 600WRAM: PNY 2GB DDR3 PC3-10666 1333MHzHD: Seagate 320GBTitle says it all. I've google my heart out looking for answers. Many say maybe power supply is bad. I tested my old PS and it still doesn't work. Try new Cable. Try every RAM slot. Made sure my CPU is nice and tight. Sigh...headache....headache.
First thing be sure the CPU cooler has thermal paste between CPU and cooler. Second thing be sure the ALL fans are running properly. Re-seat RAM and power cables. Disconnect all extra items. If you have only add-on video card leave it in. Test it with only vid/CPU/RAM connected to rule out other items. If it stays running then one piece at a time plug in the add-on's after you power off. Then turn on after each item and test to see if it runs. Hope this helps, is a place to start at the least.
The CPU fan not spinning would be my first guess but if it is spinning then the settings in the BIOS are probably wrong. Let the BIOS detect the cpu and manually enter the correct timings from the sticker on your RAM. If you can't even get in the BIOS, you need to replace your motherboard.
It could be 1 or multple issues. You can also be one of the few of the DOA (Dead On Arrival) products. My best suggestion, is to take out the graphics card first, then try to boot it up. IF no go, then try taking out 1 stick of ram, then the next. Also, ensure you have your heatsink/fan sitting on that processor with some Thermalpaste making contact. You may have your heatsink and fan is not properly seating right on the processor. last but not least, could be the PSU is just dead. Make sure you have it set to 115v as well. If you have tried all of these and still nothing, then you either have a Dead Motherboard or Dead Processor.
You might want to look at Asus website under CPU support..the 750 shows 2 different bios up dates with a URL to go to for more Info. If that's all right..try the ram...(if its dual channel) take out one stick at a time see if you have a bad stick...if you only have one 2GB it may be bad...Go to BIOS and set to safe default then try it
Are you positive you have all the power cables connected properly, the extra 4-pin ATX12V power connector near the CPU, the PCI-E power connector(s) to the video card? Otherwise, if the computer seems to start up for a couple seconds, but then switches right off, the motherboard might be shorting against the case. Did you have trouble getting the motherboard to line up inside the case? Are the motherboard screws centered properly on the screw holes? Is there clearance along all four edges of the motherboard? The other place you can have a clearance problem is the support plate for the CPU heatsink, on the back side of the motherboard. (Or, sometimes, screws behind the chipset heatsink.) The test to see if the motherboard is shorting on the case, is to pull everything out, and hook up all parts separately, outside the case. Set the motherboard on some bubble wrap or something, and hook up all the other parts. If the parts start up and run, outside of the case, then you can start looking for where it might be shorting. (That particular Thermaltake power supply is made by Compucase, and it's a piece of junk. You should think about replacing that no matter what.)
