I just removed my motherboard in order to replace a broken 478 Intel Retention Retainer Bracket, now that I put everything back I find that my computer wont start the fans try to start and stop, so I guess I have a wire in the wrong place...Now what I want to know is can I check my motherboard outside the compute without putting it back with all the cables??? and if so what cables do I have to connect to the motherboard to see if it runs....so it would be nice to try the motherboard out without putting it back in the desktop and screwing it all down and putting all the cables back to find out that it has to be taking out again Thanks in advance for any help...

a possible cause to your problem could be a misaligned offset that goes behind the motherboard, this could be shorting it out. Or as you've said you may have plugged something in incorrectly, or your powersupply is failing. Another cause could be your CPU or even the Heatsink. make sure they are firmly installed with a good quality termal compund such as arctic silver 5 between them. you can easily bench test the motherboard, but placing it on a non conductive surface, a desk for example, plug in one stick of ram, you CPU and heatsink assembly, your graphics card. plug in your PSU into the board. to turn the whole thing on, use a scre driver to short (connect) the two pins that you wold place the power swtch cable to. Do this very briefly and if nothing is wrong then the power supply will turn on and will display something to the sreen.