Your router is apparently running in so-called BootROM mode. It is a crippled IOS stored in the router's ROM. This IOS is started when the full IOS in the FLASH is erased or corrupted, or if the configuration register is set to an incorrect value.
Check the configuration register value - it should be set to 0x2102. Also, check using the show flash command if the IOS is stored in your FLASH. If it is not, it is necessary to store it there using TFTP.
Search the Cisco web site for this procedure
follow the instructions exactly.
Make sure that you can ping your TFTP server and save your original IOS file before erasing the memory.