I have a 2 year old emachine that will no longer stay on. It was turning off by itself and slowly got worse and worse until it won't stay on at all. Any ideas? Virus?

1.Go to any store that sells compressed air for computers in a can, and buy one. 2.Unplug your computer from power, open the computer case. If the computer is dirty inside as suspected, you may want to set the computer on the back porch, on a wood surface. The amount of dust, dirt, spider webs, and so on, may be great. You may want to look into buying a cheap dust mask, and wearing some eye protection. 3. Break the plastic lock tab off of the top of the can, insert the plastic 'straw'. Start at the top of the inside of your computer, and from one side. Shoot air across in a row. Drop down, make another row. Clean the inside of the power supply from the back. (Power supply is located at the rear/top of the computer case. Metal case with ventilation holes in it) Come around to the back of the computer, and clean the inside of the power supply, as well as the fan. Go back to the inside, and shoot air for the residual dust. 4. When you are satisfied it is clean, close the computer case. Plug back into power. WAIT 1 minute, turn the computer on. When a processor overheats it turns off. This is a Fail Safe feature. Keeps the processor from burning up. If the processor fan is dirty, the processor is overheating. 1.Go to any store that sells compressed air for computers in a can, and buy one. 2.Unplug your computer from power, open the computer case. If the computer is dirty inside as suspected, you may want to set the computer on the back porch, on a wood surface. The amount of dust, dirt, spider webs, and so on, may be great. You may want to look into buying a cheap dust mask, and wearing some eye protection. 3. Break the plastic lock tab off of the top of the can, insert the plastic 'straw'. Start at the top of the inside of your computer, and from one side. Shoot air across in a row. Drop down, make another row. Clean the inside of the power supply from the back. (Power supply is located at the rear/top of the computer case. Metal case with ventilation holes in it) Come around to the back of the computer, and clean the inside of the power supply, as well as the fan. Go back to the inside, and shoot air for the residual dust. 4. When you are satisfied it is clean, close the computer case. Plug back into power. WAIT 1 minute, turn the computer on. When a processor overheats it turns off. This is a Fail Safe feature. Keeps the processor from burning up. If the processor fan is dirty, the processor is overheating.