http://www.solarwinds.com/products/freetools/free_tftp_server.aspx
Step-1------1--Connect your router with Console Cable.2-Check the Flash,(#show flash)3-Romove the Flash file (Existiing IOS)(#delete flash: c1700- adventerprisek9-mz.124-8)4--Reload the router.(#reload)5--Then you can see the Rmon mode of router.
Step-2(Configure the below Command.)-------
rmon 2 > IP_ADDRESS=10.0.0.1
rmon 3 > IP_SUBNET_MASK=255.255.255.0
rmon 4 > IP_DEFAULT_GATEWAY=10.0.0.2(TFTP Server)
rmon 5 > TFTP_SERVER=10.0.0.2
rmon 6 > TFTP_FILE=c1700-adventerprisek9-mz.124-8.bin
rmon 7 > tftpdnld
rmon > Y
Step-3(After Copy completion from TFTP to router)
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rmon 8 > boot flash:c1700-adventerprisek9-mz.124-8.bin
Then you can operate your router by new IOS..