trying to share PC in same homegroup

I have three computers in my homegroup. While I have been successful in sharing folders between two, am unable to do with third one.



KR-PC is able to connect with RK-PC. but RK-PC is not able to connect to NUPC-PC
This snap shot is from RK-PC. When I put in the homegroup password from NUPC-PC, it says invalid username or bad password. What should be the username here ?
thanks.

Which computer is your "host" computer that you created a homegroup on?

If you are not able to connect with one computer, perhaps check the advanced sharing options on that computer.

RK-PC is the host computer. I am trying to access NUPC from RKPC. What will be the username here ? the password will be the one shown in NUPC in homegroup ?

User names really aren't used in Homegroups. The password is, as you say, the one on the Host computer.

If you are getting the credential window you show, do you have all the computers in the same Work Group, and on the Advanced Sharing options, do you have it set to let Windows handle Homegroup connections? Normally all you need to do on a non-host system is select Join a Homegroup and supply the password. This option should be displayed in the Network and Sharing Center, just below the globe and across from the House icon next to Local Area Connection.