for some reason or another, the router was not able to boot its full IOS and has booted into rommon mode.
this could be intentional with setting the configRegister or it could be due to a software failure on your flash/bootflash or a phyical problem with the device.
you may need to get an IOS on the device so it can boot fully.
see the link below for info on the rommon recovery procedure, which will show you how to get the router to boot normally:
1700 routers -
http://www.cisco.com/en/US/products/hw/routers/ps221/products_tech_note09186a00800942dc.shtml
2600 routers -
http://www.cisco.com/en/US/products/hw/routers/ps259/products_tech_note09186a0080094a0b.shtml
1600 routers -
http://www.cisco.com/en/US/products/hw/routers/ps214/products_tech_note09186a0080094013.shtml
there are many different links for the different router models. goto cisco.com and search for 'rommon recovery' if you don't see your router listed above. (most of these router models have the same process for this task so any of the above docs may work fine)
