ive recently been having issues with my computer just shutting off at its own whim. i was convinced it was the switch but i disconnected the switch and the computer still decided to start up then about two minutes later shut down. i disconnected both cd rom drives to see if may be a power issue and that solved nothing im just looking for some imput on the issue

Sudden system freezes/lockups, crashes, reboots and shutdowns can be caused by many things - that often makes it very difficult to troubleshoot.

One of the most common causes is overheating. Heat is the bane of all electronics. To control heat, computers use fans to pull cool air in, and expel hot air out. Unfortunately, this same process also draws in heat trapping dust, dirt, hair, dander, microscopic critters that eat dander, and microscopic droppings from those microscopic critters. Heat can cause problems with the motherboard itself, the CPU, the graphics card, and more. So, you need to make sure your system is clean of dust and dirt.

Cleaning the insides of the computer presents a problem because sticking your hands or cleaning tools in the case without care can result in ESD damage. Yet it is a user responsibility to keep heat trapping dust from blanketing heat sensitive devices inside the computer. And today's computers generate a lot of heat. In particular, the CPU and increasingly, the GPU (graphics processor unit). Both can generate as much heat as 100 watt (or more) light bulbs!

I recommend inspecting monthly, and cleaning if necessary. While observing ESD precautions, I take my systems outside and use a soft paint brush and compressed air from an air compressor. With compressed air, you can blast out the power supply unit (PSU) (make sure you do it from inside the case). Alternatively, you can use cans of compressed air to clean the PC. (Note: Even with cans of air, I still recommend cleaning outside. There's no need to blow the dust back into the room, ready to be sucked back into the computer by the fans).

With care you can use a vacuum cleaner and a soft paint brush. But it is important to understand that air and dust particles zipping past the nozzle of the vacuum can (will!) generate static in the nozzle. This is a VERY SERIOUS and legitimate concern. But so is heat! And using some sort of forced air is best at removing heat trapping dust, so if compressed air is not possible, vacuuming is the next best thing. And you can do it indoors.

Even a tiny static discharge can easily destroy sensitive devices. Therefore, it is absolutely essential ESD precautions are observed to prevent static buildup, discharges and possible damage from ESD, as well as physical damage from banging the nozzle into fragile devices, or scratching the motherboard. But the process is simple. Power down and unplugged the computer. With a soft brush in one hand and the vacuum nozzle in the other, extend a finger on your nozzle holding hand out past the tip of the nozzle and plant that finger on bare metal of the case. Touch the brush tip to bare metal to discharge any static there, then simply use the brush to sweep the dust into the vacuum. With your finger(s) touching metal, and your hand wrapped around the nozzle, no static can build up, no ESD damage can occur. Every time you reposition the nozzle, touch metal with an extended finger before moving in close.

Note: As with the compressed air, resist the temptation to see how fast you can make the fans spin. You can make them spin faster than designed limits and damage the bearings. I use wooden Popsicle sticks to hold the fans in the power supply stationary.

While inside the case, inspect the motherboard for leaky capacitors. Leaky capacitors are a common cause of sudden system crashes. Look for white to dark brown dried foam leaking from the tops or bottoms of the capacitors. The capacitors look like tall soda cans, many of which surround the CPU socket. Bulging capacitors are a sign leakage is about to occur. A motherboard with leaky capacitors can be repaired, but often it is more cost effective to replace the motherboard.

Perform a complete malware scan. If you don't have a full arsenal of anti-malware tools, see Cleaning Out Malware.

Sudden shutdowns can also be caused by an overstressed or failing power supply. If you have added hardware since the power supply was new, it may no longer have sufficient power to meet the needs of the computer. As PSUs age, they get weaker too. Testing a stressed or intermittent power supply is best left to a qualified technician. Testers, such as the FrozenCPU Ultimate PSU Tester are great for testing supplies that have already failed. The easiest way for the typical user to determine if their supply is good is to swap in a known good supply designed to meet the needs of the computer and see if the problem remains, or goes away.

Use the eXtreme PSU Calculator Lite to determine your power supply requirements. Plug in all the hardware you think you might have in 2 or 3 years (extra drives, bigger or 2nd video card, more RAM, etc.). Be sure to read and heed the notes at the bottom. I recommend you set Capacitor Aging to 30%, and if you participate in distributive computing projects (e.g. BOINC or Folding@Home), I recommend setting TDP to 100%. Then look for brands listed under the "Good" column of PC Mechanic's PSU Reference List. Don't try to save a few dollars by getting a cheap supply. Digital electronics, including today's advanced graphics cards, need clean, stable power. A good, well chosen supply will provide years of service and upgrade wiggle room.

If you look in Event Viewer to the moments just before the crash, there might be an error listed - although typically these type crashes are so quick, the systems do not have time to write an error.

ok heres my status update, i completely eliminated all dust from the comp, went as far as to by a new case which drastically improved my ventalation and im still having the issue, the thing that gets me is even when the power switch is NOT plugged in the computer will still turn on and about 2 mins later turn off like rapid turn off, turn on a min later then 2 mins later turn off again, ive timed it and it turns off and on in the same intervals every time, so im stuck i have a pretty good knowledge of computers and this has me totally perplexed

when the power switch is NOT plugged in the computer will still turn on

You need to look in your BIOS and make sure all the Power on options are disabled. Look for Power on Modem, Power on LAN, Power on Mouse, and any other such items.