So my family has had this computer, a 2003 HP Pavilion 754n, and one day the PSU decided to give out. I could have just swapped the PSU but the computer was horribly outdated so I decided to completely upgrade it. This list of parts I bought are as follows:
This is my first time upgrading/building a PC, and all the parts seemed compatible with each other according to my research.
I carefully installed everything and upon the first boot, the fans and hard drive began to spin. However I had no video signal whatsoever, not with VGA, DVI, or HDMI. I tried several monitors to no avail. I even tried with a PCI-e graphics card but got the same result. Flash drives and everything plugged into the mobos inputs do not light up, only a PS2 mouse that I had laying around.
Additionally I did some reading on motherboards not sending video signal and came across this thread:
It may very well be a defective board, since the motherboard contains the majority of the components of the system. Try 'bread boarding' it. Take it out of the case and set it on some insulated surface like the box or pad it came with. Connect the monitor to the onboard video. Remove everything (including graphic card) from the board except the CPU and heatsync, 1 stick of RAM. Connect the PSU's 24 pin and 4/8 pin CPU power connector to the board. Power up the PSU. Short the two F_Panel pins that the PWR SW. would plug into to start the system. The system should be able to boot to BIOS. If you get no display, it is either the board or the CPU. Most likely the board. To shut down, either keep those 2 pins shorted until the system stops or turn off the PSU.