Windows 7 Share Problems (and Server Question)

Hello all,

I got a question which I hope you all may know the cause and would like some professional opinion too. It will be asked in two topics "Share Problems" and "Server".

Thank you for your time!

{SHARE PROBLEM}
We got 5 computers, 2 is running Windows 7 Professional, the other 3 is running Windows 7 Home Prem.

All of them are under the same "Workgroup" and "Homegroup" as well as the same settings for Network (Advanced + Homegroup). Also all are using Admin account access (Owner Admin settings) for their computer respectively.

Now when I set one of the computer to "Share" a folder (Home Prem), I just gave "Homegroup" with "Read/Write" access.

All computers except for one computer (Win7 Professional) is able to just click on the Network and access the folder, it is just one which will always ask for a "User/Pass".

Considering everyone has the same settings, I don't see why the Win7Pro is having this trouble and always asking for a User/Pass.

The other 2 Home Prem and the other Win7Pro can easily access it without any problems at all (click on Network -> WinHPrem computer -> Shared Folder).

Is there any ideas and troubleshooting I can do to resolve this?


{SERVER}
I am planning to change one of the PCs I have to a dedicated server.
The primary purpose is to allow access within the "work network" (all computers in the 1st location) and "outside network" (2nd location having access to the database at the 1st location)

Obviously a server would be an idea choice as it allows user/pass configuration, dedication server configuration, security and more.

From what I can research, Windows 2012 R1 is the latest but that's been out for 2 years with a mileage of about 2018 for support.

Is that the most idea OS to use for this scenario?

I don't know if Windows 7 is capable of it but I don't really have much luck finding an absolute answer for it (leading to Windows 2012).

I know it will take additional research to setup user/pass as well as dedication IP (for 2nd location to access to 1st location), but that's fine.

I just need some opinions on how this should be done.


Thank you for all the help, if there is any additional information(s) you would like to know, please let me know.

- LL