My computer is not working shows keyboard erro and stop

Check your computer to make sure it is actually sending out a signal. You can do this by hooking up another working monitor. If the other monitor works, there maybe a problem with the original monitor and it may need to be sent for service repair.

your possessor fan dos not properly work or fan casein do not properly instal or your power supply faulty.

Your Video Card (Graphics Card) is probably bad. To isolate the problem connect another monitor to the computer. Borrow a monitor from a neighbor, friend, relative or co-worker and connect it to the computer. If the Borrowed monitor displays the same NO Signal Message then your video card is bad. If the Borrowed monitor displays and works correctly, then your original monitor is bad. The fact that your monitor displays the No Signal Message on it shows that the monitor is ok.

If you have a laptop, the video will show on most systems when you reboot without you having to do anything. Some systems will require you to hit the FN (Function key) + F1 thru F12. Hold down the FN key then hit the correct key for displaying on the monitor (F1 thru F12). The correct key will normally have CRT/LCD on it or it will have the icon of a display.

No signal at the monitor indicates (if you know the monitor is working ok) a failure of the graphics chip or graphics card, The lack of indicator light on the num lock LED and the lack of power to the mouse would indicate that there is a major issue with the motherboard.
you can try using another monitor to confirm the problem lies with the graphics, and in the case of the keyboard and mouse, swap them for a usb version, if they work, the Ps2 ports are probably damaged.
I'd be thinking of replacing the motherboard

0 problem with ur computer u need to change the memory of the harddrive if the p problem persist change processor or mother board

The first thing to check is--is your computer actually running?
It sounds like your computer is either off or it is not sending a video signal to the monitor.
If there was a signal going to the monitor, you would be seeing something other than self test.
There is also probably a menu button on the monitor. Find it and push it to reset the monitor.
Now check your computer--preferably with another monitor to see for sure what is going on.

I agree, if you did a combo of keystrokes (re: cntrl+F5 for monitor) thats only a shortcut keystroke and should be able to do and undo all changes in "control panel">"display">"settings">advanced

You'll need to purchase an adapter like the one found at monoprice.com:
http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10401&cs_id=1040110&p_id=70&seq=1&format=2. Then just plug it in :-)
Steven

All the drivers for you motherboard are available here: http://www.asrock.com/mb/download.asp?Model=775i65GV

Check if motherboards you connect the monitor into has a video signal frequency range that the monitor supports.