The first thing I look at when dealing with an eMachines desktop computer, is to see;
1) If it is dirty inside.
If the cooling system is clogged up with 'Gunk' the Processor will overheat. Too many times of this causes major problems.
Air is drawn into the front of the computer, and expelled out of the back. The air flow cools the computer hardware components inside the computer.
Hardware components such as the Processor, graphics chipset, motherboard chipset, Ram Memory, and Power Supply.
If the cooling system is clogged, the cooling capacity drops tremendously.
Computer on a table, computer unplugged from power, computer case open.
Observe Anti-Static Precautions.
Your body carries Static electricity. Static WILL fry out (Short Circuit) the delicate hardware components inside the computer.
Computer on a table, computer unplugged from power, computer case open, TOUCH an unpainted surface of the metal frame.
This action will relieve your body of Static.
Should you leave your computer in the middle of working on it, be SURE to Touch the metal frame again upon your return ]
Use a can of compressed air for computers. Attach the plastic straw provided to the nozzle. Break the plastic lock tab off of the top of the nozzle. (Used for shipping)
Place the straw tip in the upper left corner, (Inside), and spray air across to the upper right corner.
Squeeze the trigger in all the way as you start, let go of the trigger as you reach the other side.
Drop down a space, and spray across again. (You can watch the cleaning action of the air spray, to determine what the space drop should be. It isn't critical for the spacing. Just what you determine to be best)
Keep dropping down a space, and go across in rows.
Pay special attention to the Fan sitting on the finned Heatsink, (Which sits on top of the Processor), and the finned Heatsink.
Example of an average Fan/Heatsink combo,http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=578161&CatId=795
Left-click on the Fan/Heatsink photo to enlarge.
The Fan's blades, center hub, and surrounding cage (Shroud) need to be clean.
I use Q-tips to stir the dust, then follow with compressed air. You don't need to remove the dust, just break the 'crust' so the air can remove it.
(Where the fan blades meet it's center hub, needs to be clean also)
The fins of the Heatsink need to be clean. In-between the fins, and on the outside of the fins.
The Power Supply is the rectangular shaped 'box' at the upper back of the computer. This is where the power cords plugs into. It has ventilation holes in it's case.
Example of an average ATX power supply,http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4435072&CatId=1483
The side shown with ventilation holes is the outside of the Power Supply. The opposite side you'll see from inside the computer has ventilation holes also.
Hold onto the plastic straw with one hand, and the can of air with the other. Insert the tip of the plastic straw about an inch inside a top ventilation hole, on one side. (Front of Power Supply, inside the computer)
Spray air, then move to another upper ventilation hole. Now move down, and go across using the ventilation holes. Finally shoot air in the bottom ventilation holes.
Move to the Back of the Power Supply, (Outside of computer at the back), and clean the Fan, it's surrounding cage, and shoot air into the ventilation holes of the Power Supply.
When you are satisfied the computer is clean, let it set for 5 minutes or so.
Allow any moisture that may have developed from using the can of air to dissipate.
Plug the computer into power.
WAIT 1 minute. Turn the computer on.
The second thing I look at is an eMachines power supply.
eMachines are budget computers. Nothing wrong with that, but the manufacturer saved money by installing low quality power supply's.
I replace the Power Supply with a KNOWN to be good, Compatible unit, for a test.
Main problem for desktop computers is they are dirty inside.
Next in line is a bad Power Supply.
A bad Power Supply (Weak voltage rail) will cause all kinds of software problems. It isn't a software problem. It is a hardware problem.
If you state in a Comment as to the Model Number of your eMachines, I may be able to give you a link for opening the computer case. (It's on the back of the computer tower next to the Windows product key)