For this kind of problems, it is also possible that your hard disk has a bit of a problem. For hard disk problems, there are several solutions: like repairing the Operating System, by inserting the OS disk into the compact disk drive, then choosing Repair and following the instructions that best suits the situation of your computer. Aside from the repair, reformatting the hard disk would also be a solution, although this option is the least liked by users since it usually erases all the files located in your computer unless back ups have been made. Making back up for files is possible by using the same compact disk used for reformatting or reformatting. If the files are no longer important or needed by the user, reformatting the computer could possibly solve the problem.
You may try to reconnect the systems wiring from the main connection between the power supply and your motherboard. Then also reconnect the cabling between the hard drives and the power works, after doing so, attempt turning the computer on. If the computer still doesn’t turn on, seek for a power supply that provides higher wattage. This is usually suggested for computer with extra gears, like tv out, additional drives with higher capacities.