How to Fix - Computer powers on, but does not boot [Solved]

When you press power button it's lights up but PC doesn't start.There might be few things causing for this problem.
First of all listen to beep sound when you press power button.There is several beep sound patterns indicating the problem caused to boot failure.

1 Beep
Reseat/replace memory, troubleshoot motherboard.

2 Beeps
Reseat/replace memory, troubleshoot motherboard.

3 Beeps
Reseat/replace memory.

4 Beeps
Troubleshoot motherboard.

5 Beeps
Troubleshoot CPU, motherboard.

6 Beeps
Troubleshoot keyboard, motherboard.

7 Beeps
Troubleshoot CPU, motherboard.

8 Beeps
Trouleshoot display adapter, motherboard.

9 Beeps
Replace ROM BIOS, troubleshoot motherboard.

10 Beeps
Troubleshoot motherboard.

11 Beeps -
Troubleshoot L2 cache, motherboard.

12.Continuous Beeps
Troubleshoot memory, display adapter, motherboard.



NOTE: Before making any attempt to remove or replace any part inside the casing, ensure that the power is off.

If it's a RAM related problem try to remove it and place it in another memory slot on the motherboard.
If Video card causing to this boot failure you have to buy a new video card.

Also remove CMOS Battery carefully.This will reset BIOS Setting to DEFAULT.Wait few minutes before reseating the battery.

Important Note: Not all motherboards have removable CMOS batteries. If the battery won’t come loose, don’t force it.