Why is display blank except for blinking green light on left?

clean ribbon cable contacts on control board

Have you inadvertently programmed your microwave for "autostart"?
Your model microwave has the ability to be programmed to go on at any given time of the day/night, even when you're not home so that you can have a defrosted and cooked meal waiting for you when you get in.
I know that if you hit the 30 sec button or the minute button when your micro is programmed to autostart it will tell you the time that it's programmed to autostart or the amount of time that's left for it continue cooking.

Have you tried unplugging it for a few minutes?
This should clear it's memory and then all you'll have to do is set the time on the regular clock if you want.

Here's where you can download and read your owners manual for further instructions on how to use the autostart feature and everything else:

http://www.fixya.com/support/p113437-emerson_mw8107wa_1000_watts_microwave/manual-11318

It is still under warrantee if under a year. Contact your dealer who you bought it from-it should be repaired or replaced free of charge.

The owner's manual is here. On page 10 we find:

COOKING IN ONE STAGE
1. Press the POWER button; the Microwave and High
Cook indicators will light and “PL 10” will light in the
display.
2. Press the POWER button different times to set the
desired power; the display will show the percentage
you chose. If selecting power level 70%-10%, the
Low Cook indicator will light instead of the High
Cook indicator.
3. Press number keys to set the desired cooking time.
OPERATION(CONTINUED)
4. Press the START/+30SEC. button to start cooking;
the Microwave and one of the Cook indicators will
blink and the display will countdown the remaining
cooking time in minutes and seconds. It will beep
five times when cooking is completed.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

I have arranged for a GE technician to visit my home this Thursday.
Thanks for the e-mail

The GE JKP62G Microwave / Oven combination has an internal fuse behind the control panel for the microwave. The oven will operate but the microwave will be totally dead (no light, no clock). Turn off the breaker for the oven at the fuse box (30 Amp double breaker). In order to replace the fuse you will have to open the door to the microwave, remove the two screws (Torx) from the front control panel (located on the left edge of the control panel), wiggle the panel to the left (there are two metal tabs that stick into the metal frame of the microwave on the right of the panel) and then tilt the panel down from the top. There is a metal bracket that holds the control panel to the microwave at the bottom (don't remove it). Look towards the top of the microwave inside the area behind the control panel and you will see a 15 Amp screw in fuse. Replace the fuse and that should fix your problem.

from what your describing it sounds as if you have burnt the antenna off of the end of the magtube if this is the case if your microwave is no longer under warranty due to the cost of the part you may be better off to purchase a new microwave.

The first thing to try is a "hard reset". Unplug it from the power line for a minute, plug it back in, set the clock, then try again.

Let us know if the hard reset doesn't fix it.