Usually the self-test implies that the monitor is fine. You have eliminated the pc being the fault by trying another pc so its definately not the pc.
I would try unplugging all cables from the monitor (whatever is possible), and then holding down the on/off button on the monitor for 30 seconds. Plug the cables back into the monitor and re-wire it to your computer. Once this is done, switch your emachine pc on and keep tapping Del to get into the BIOS.
If you get the same result, check the connections and check for any bent or missing pins. Only other way to make sure it is the monitor is to try another monitor on your computer!
Other than this, you'll be looking at getting a new monitor, or ringing the manufacturer if in warranty
Kash
April 2006