When you get home, try this.
1. First, remove the sound card and other internal perephrials (leave the monitor and mouse etc attached) so you have just the video card, ram, motherboard, hard drive, and processor connected. make sure the power supply is connected securely to the hard drive, motherboard, and make sure the core voltage plug is plugged into the motherboard.
2. locate your system speaker wire. make sure it is connected to the motherboard if the motherboard does not have an integrated speaker.
3. with the sides of the case off, power up the computer. check and see which fans are spinning. if the power supply fan is the only thing spinning, you have a dead motherboard or a bad power connector. if the fans hooked into the motherboard (processor fan, etc) spin up, then the motherboard should be operational. At this point if the processor is bad, the motherboard should emit a series of beeps. If it does not beep, it may be trying to boot. listen for your hard drive to spin up. if the hard drive starts spinning, it may be your graphics card that is out.
if nothing happens at all except the power supply fan comes on, there could be a break in the main cable somewhere, or a short.