See if the problem is the Power On switch, or Power Supply, Kimberly.
Bypass the Power On switch.
The test does Not involve the Power On switch, or it's wires.
1) First follow Anti-Static Precautions.
Your body carries Static electricity. Static WILL fry out (Short Circuit), the delicate hardware components inside a computer.
Relieve your body of Static BEFORE, reaching inside your unplugged from power computer.
Computer on a table, computer Unplugged from power, computer case open;
TOUCH an unpainted surface, of the metal frame of the open computer case.
This action will relieve your body of Static.
IF you leave your computer in the middle of working on it, be SURE to Touch the metal frame again upon your return.
2) Open the computer case:
Viewing the computer from the Front, the Left Side Panel removes.
There is a Thumbscrew, or Philips screws along the edge of the left Side Panel.
Loosen the Thumbscrew/s all the way, or remove the Philips screws.
Use the fingerpull molded out of the back of the left Side Panel, and pull the Side Panel to the rear of the computer.
May only pull back about 1 inch, then is brought straight out to the side.
You also may wish to remove all cables, and lay the computer on it's side, opening up. Easier to work on, will not affect the computer.
(You could turn the computer upside down, and it will work just fine.
Not the optical drive though! Disk would fall out, lol!)
There is a main power cable going to the motherboard.
It is a 24-pin ATX main power cable.
This is a general example of a 24-pin ATX main power cable,http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain24
Here it is shown in the ET1300-02,
Look at the main view. Has four smaller views underneath it, and three dots after the four views.
Click on the 3 dots.
This takes you to a small screen that shows many views of the ET1300-02.
Left-click on the middle photo in the second row.
Shows the left Side Panel removed.
The 24-pin ATX main power cable is in the middle, and next to the red SATA cable that goes up to the optical drive. (CD/DVD drive)
24-pin ATX main power cable plugged into the motherboard, a jumper wire is used on the 24-pin ATX main power cable's connector.
The preferred jumper wire is a straightened out paperclip, bent into a U-shape.
The top of the U, is wrapped a few times with black plastic electrical tape.
This taped area is for your fingers, and thumb to hold onto.
Turn the U-shaped jumper wire upside down. The 'legs' are what is used.
Looking back at the Playtool link above, look at the view to the far right.
See the Green wire?
The green wire is the Soft Power On wire. If it is jumped with a wire that is a Ground wire, the Power Supply is supposed to turn on.
Note where the wires go into the connector, of the 24-pin ATX main power cable. This is the Back of the connector. This is also where the 'legs' of the jumper wire goes.
The 'legs' of the jumper wire goes down into the squarish socket holes, RIGHT NEXT TO the existing wire that is in the socket hole.
One leg goes down into the socket hole with the Green wire.
Slides past the insulation of the wire, and touches a metal terminal down at the bottom of the wire.
All wires going into that 24-pin ATX main power cable connector, end in a metal terminal.
The metal terminal looks like this, (Only smaller),http://www.molex.com/molex/products/datasheet.jsp?part=active/0002081202_CRIMP_TERMINALS.xml&channel=Products&Lang=en-US
Looking at the photo in the middle on the Playtool link, you can see the rounded tips of those metal terminals. (They go over contact pins on the motherboard's connector)
The jumper wire MUST touch that metal terminal.
The other 'leg' of the jumper wire goes down into ANY socket hole, that has a Black wire in it.
ALL Black wires are Ground wires.
Voltage used? 5 Volts DC.
In comparison two D cell flashlight batteries store 3 Volts DC.
Not saying there may be a spark. For this reason you may feel safer wearing a glove on the 'jumper wire hand'.
The contact period is no more than 2 seconds. The Power On switch is a Momentary Contact Switch.
IF, the Power Supply comes on you have a bad Power On switch.http://www.directron.com/atxswitch.html
IF, the Power Supply does Not come on you have a bad Power Supply.
For additional questions please post in a Comment.