how to reboot from beagle board

i actually booting angstrom on this beagle board ,but icouldnt
install x windows for gui aplcation, suddenly terminal window any new
message is niot came how can get beagle board prompt ,how i can boot
beagle once again , fdisplay not shown logo beagle board

Follow the instructions found here to restore it to the factory software loads:

http://code.google.com/p/beagleboard/wiki/BeagleboardRevCValidation

Gerald