Problem with Console Port

[Khurrum Shahzad]

Hi,   I am facing a problem with my  2501 router. It was working fine, but for the last few days I am not able to connect to the console port of the router. It shows nothing on the screen when I try to connect and press enter. When I checked the Signal level of the console port on my Break Out box, it showed me the continuous LOW status of TxD signal. When I reboot the router, it shows me the startup messages and finally after showing all those messages it  hangs and TAKES NO INPUT from the HYPER TERMINAL. I have also tried many terminal Software like Telix, Teraterm. The router has no prior configurations (as I did an ERASE STARTUP CONFIGURATION before), so I am not able to connect via TELNET or AUX port. Is there any way out??? Can I replace NVRAM of this router with any other NVRAM having configuration and then connect with the router with AUX port or via TELNET? Is NVRAM Of 2501 router replaceable? Khurrum