Hello,wen i press the power button my system is not responding...and there is no beep sound.so please give me any solution to solve this problem.
First things first... let's start with the obvious and work to the solution.
1) Does your computer have a 2-way toggle switch on back of the computer near where the power cord plugs in? If you do, try switching it to another position. I can't tell you how many service calls my customers could have avoided by simply checking any 'Standby' or 'Power' buttons on their equipment. Or power cords....
2) Is the power cord plugged into the wall or a surge protector? If it is plugged into a surge protector make sure that it is working correctly and any circuit protection that may be on the surge protector has not been tripped. Try switching it back or resetting it if you have the ability. Try plugging the PC directly into the wall outlet after confirming the outlet has power. It is possible for a perfectly good outlet to go bad over time depending on a number of variables too numerous to list for our purposes...
((DISCLAIMER)) The following steps should only be undertaken if you are comfortable around electronics and electricity. Troubleshooting a PSU takes a little bit of knowledge about both. Opening or working around energized parts does impart a slight hazard of electrocution and should not be undertaken by yourself unless you are prepared to assume that risk. The following is merely a recounting what I have done, experienced, and learned while working through my own troubles. I assume no liability for injury to your person or property.
3) Have you taken the cover off of the PC? If you attempt to do so, make sure you unplug the PC first. Once PC is open you can plug it back in but be mindful that there is electrocution hazard inside the PC and potential to do damage to components if you come into contact with them. Do a visual inspection for anything abnormal, i.e., burned wires, smell of burnt electrical components/plastic, scorch marks on the motherboard or side of PC case, fans/cards hanging by wires, rabid squirrels fiercely guarding piles of nuts... anything that just doesnt look right. Keeping clear of the interior of the PC, turn on the power to it and tell us if there are fans running. You should have at least your case fan and the fan on the power supply running. If not, then the likely problem is that your power supply has failed. Depending on your tool/technical skill you may decide at this point to proceed with troubleshooting your power supply.
4) The EASIEST and SAFEST way to troubleshoot a PSU would be to put in a different power supply if you have one on hand. Even borrow one from another PC you have or sometimes your local PC repair shop may loan you one or sell you a used one for very cheap. I pick them up for about 5 bucks from the local guys here. DO YOUR BEST to VERIFY that the PSU is in good condition before installing it. Make sure you have the correct type as well, that all of the connectors leaving the power supply match the types of connectors you have on your suspect one. Have it tested at the local PC store if they do that in your town.
I need a little more information to continue at this point. First, confirm that the aforementioned fans are running when you turn on the PC. Do you have any lights? Is it just a stonecold silent box? What type of PC is it and roughly how old is it?