I just recently moved into my dorm in college. I brought my desktop with me thats custom built. I was setting it up the other day and found out that the computer was turning on, but my monitor was not getting any response. I kept trying to hook it up, because in the past the order in which the monitor was attached to the computer mattered if it received signal. I opened up my computer, my graphics card fan was spinning and everything else was plugged in correctly. I tried plugging it into my TV, but that didn't work either. After about 20 minutes of trying, I noticed that my keyboard was not working anymore either. I was puzzled, I noticed that my mouse was working and my ipod connector was receiving power aswell. I kept turning on and off my computer and realised I wasn't recieving a post bios beep (i'm preety sure thats what its called). I did some research and didn't find anything. I attempted to clear my CMOS by the button on the pack of the motherboard, but that didn't help. At this point i'm thinking that my power supply isn't pulling enough power from the wall, or something in the move of the desktop messed something up. Please help me out. Everything in the system is stock, and nothing is overclocked.
The breadboarding thread has a paragraph about how to build and test a PC in stages.
Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.
You can turn on the PC by momentarily shorting the two pins that the case power switch goes to.
You should hear a series of long, single beeps indicating memory problems.
Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU.
If no beeps:
At this point, you can sort of check the PSU. Try to borrow a known good PSU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.
The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.
This checks the PSU under no load conditions, so it is not completely reliable. But if
it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.
If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card. Silence or long single beeps indicate a problem with the memory.
Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.
Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step.