A manual would be great and better for it eliminates mistakes which could not solve the problem at all and worse send you off buying a new board due to a short you created when you hastily did the operation. Boards come in several versions from several manufacturers, and if you’re like me who sticks to a select group of manufacturers, chances are they will have the overall same labels that allow easy understanding of the board even without the manual. If the reset pins come in the form of a three pronged arrangement, then there should be a jumper that shorts out two of them which in it’s current state would be the normal setting, switch the pins using the jumper and short the pins labeled reset, wait for a few minutes for the bois to reset then return the pins to the normal position. Some boards have labes some don’t and have numbers that have to be referenced with the manual.

First, if you can get hold of nifty utilities from trusted sites of the internet, then that would be easier but it can sometimes corrupt the bios of the system as it forces a program to open the said part of your computer system so be cautious and read all recommendations and instructions in the readme file so you don’t cause further problems.
If you’re in a hurry and don’t have a second computer to do a search, you can always consult the motherboard’s manual or simply look at the board for any pins that are labeled BIOS reset/normal. This is a failsafe mechanism which is built in by manufacturers into their boards to allow use of a locked system as yours.

If you by chance got yourself a good deal on a second-hand computer that works just right and is affordable enough o allow you to upgrade some parts then you indeed got a good deal. As you get home, you setup your prize and power-up only to find that the system is locked down by a password. A boot password or worse a system password can prevent access to the contents of the hard drive or the system itself leaving you stranded in the boot-up menu. Don’t fret, for there are ways to get around the problem and these work almost all of the time in getting you up and running in no time at all.

Some motherboards are so sensitive to cooling that no fans connected to the on-board fan connectors would prevent power-up to avoid ruining the processor (this would be the case if you were using externally powered or special/exotic cooling systems) try plugging in a fan or two to see if it works. The worst case is to get the lights and fans working but still there are no beeps, display or other signs of life for it may be a signal of a dead board or power supply.
If your bare systems now functions, you can then add your components one at a time so you can continue to eliminate any problem device. The prices of computer parts have indeed gone down so much that they are affordable to most. If one does not want to spend all the time tinkering and wondering what is wrong then a trip to the computer repair shop would be an easier alternative.

Next, check if the power supply has a switch at the rear if it is on (older models) and see if it works. Check for any foreign metal objects that may be stuck between the board and the case which is shorting it out, again the protection circuit would prevent power up to avoid damage to the various sensitive electronics. A faulty motherboard fan can also be causing the problem so check the fan if it works. You might have also forgotten to connect the power button to the board (along with the reset button) so check that too. A shorted reset switch can also keep the board in a state of permanent off, unplug it to see if that works.

Modern boards use plastic stand-offs to which the board simply snaps into place or is fastened to by ties. Older PC casings use brass ones that need paper or cardboard washers for the task. There may also be an issue with the alignment of the board itself (there was an issue with Gigabyte boards sometime back that had the whole board sagging in one place of the other which prevented the memory modules from seating properly. Thanks to answersthatwork.com for the details ) Use plastic tie-downs where a plastic tie is used to pull the board into alignment to solve this type of problems.

If there is still no activity, re-seat the memory modules and video card for they may not be properly seated and locked in place(some boards and cards have locking mechanisms that prevents them from unplugging themselves as the heat goes up when it is used due to thermal expansion). There are some motherboards that have issues with grounding; any contact with the casing (which is normally grounded to the earth prong of the power supply) would activate a circuit in the power supply that prevents it from working properly to avoid frying any sensitive equipment. Isolate the board by checking the stand-off and ensuring they are isolated from the casing.

If you have just re-furbished your computer say replacing parts (memory, video cards, hard drive and other bare essentials) make sure all power connections are properly seated and connected then try to power-up. If that fails, try to un-plug and re-plug all cards and connections (IDE cables, SATA Connectors, power supply connections, etc.)
connections to ensure they seat properly (it would be nice to check for bent pins before you re-plug them in their proper sockets for that sometimes happen) and check for broken pins that may be preventing proper connections. Re-check what you have done by powering up and see if that works.

There are a couple of very easy steps that would allow you to troubleshoot a motherboard that doesn’t power up but be sure to get a grounding wrist strap to dissipate any static electricity that would kill any electronics you may touch. Make sure all power connections are unplugged before servicing a computer to prevent stray electricity from kicking you with a jolt of electricity. As with many PC problems, it would be best to strip down the PC to a bare-bone system, which would be the, Power Supply, Motherboard, processor, memory, hard drive and the necessary CPU fan. Take out all peripherals that may be connected to the computer and un-hook all connected printers and other devices. This would allow you to do an elimination process whereby you get to add components that may be causing the failure to power up.

If you have no way of getting proper grounding (which you should) insulate yourself from the floor by wearing shoes or stand on any insulating material such as a block of wood. Proper grounding prevents the circuitry of all electrical devices from frying in the event of failure and it carries away dangerous current from them sending them to the ground instead of through your body. Having grounding installed is not only necessary for safety but is common sense. Check out with an electrician so you can get your power source properly grounded to prevent injury to you and the other members of your family. SHOCKING!!!! Isn’t it.