Question : Cisco 1721 wr mem not saving

I just did a write erase of our cisco 1721 router so we can completely rebuild the configuration.  After that write erase I did a reload.  I am using hyperterminal to connect to the console port for setup.  Well I logged in after the reload and began the configuration changes after which I did a "wr mem" to write the changes to memory.  Well I powered off the router and brought it back up again and my changes have been lost.  I even did a few changes again and used the "copy running-config startup-config" , but whenever I power off and come back in on the console port the changes are gone.  What is going on????

Answer : Cisco 1721 wr mem not saving

Your configuration register may not be set correctly and the router may be ignoring the configuration in NVRAM (startup-configuration).  Change the config register to the following:

router>en
Password:
router#conf t
router(config)#config register 0x2102