Hi Nilesh,
if you have just one router and two users you can cerate just this two users with limited access.
conf t
username user1 privilege 1 password cisco
username user 2 privilege 5 password cisco
privilege exec level 5 show running-config
user1 can log into the device, bat cannot do anything. I really don't understand for waht reason you want him then to login to the device.
user2 can log in and execute the show running-config command
when the two user log in by telnet don't forget to add this command to your vty line
vty 0 4
login local
regards
alex