when i turm my computer on, windows will not start. the computer runs but i get nothing on my screen and my mouse and keyboard wont light up. any ideas?

http://www.howstuffworks.com/power-...
How PC Power Supplies Work

Mostly on Desktop computers----
DUST collects inside computers, and can cause hardware
damage, overheating, faulty fans, faulty drives
Is yours clean.????
http://www.makeitsimple.com/project...
^^^ Some pictures ^^^

Look for leaking or bulging capacitors on the motherboard.
http://www.pcstats.com/articleview....
Some pictures of them

HARDDRIVE:
Possible that the harddrive is not running at its normal speed,
freezing up or slowing down. Or has quit.
My computer took 20 min. to boot the other day.
I was watching the HDD activity indicator light,
and it would remain on, and not rapidly blinking.
Mechanical devices do have problems.

Harddrive manufacturers have software for download for testing HDD.

MONITOR PROBLEMS:
A yellow,or orange, monitor indicator light indicates
no signal is getting to the monitor from the video
card. Could be the card is not sending a signal, or
problem with the cable or connectors.
Card may not be seated properly.

http://www.memtest86.com/
Memory(RAM), test program for downloading

Thank you

The first thing to look for when powering up, is the normal single beep. If you don't hear that, your motherboard is not working and your system is completely dead. This can be a power supply or motherboard problem. It can also be caused by a defective device connected to the motherboard, which is preventing the motherboard from operating properly.