do a "hard reset"using a paper clip, insert it into the "reset" hole on the back side, located just above the ROM panel. While pressing this reset button, push the "on" button on the front.
Make sure ROM and battery are back in place.
This should get your power back, however, you' ve reset the entire system. It will start as it did when you purchased it (if you bought it new). Any softwear or files stored before you removed the ROM will be lost. Such files as Contact info will be restored when you sync.
Have fun :-)
