Windows – Renaming computers via command prompt

Try this on the Windows 7 machine:

1. Open Administrative Tools -> Local Security Policy.
2. Click on Local Policies -> User Rights Assignment on the left.
3. Double-click "Deny access to this computer from network".
4. Select Guest and click Remove.
5. click OK.
6. EDIT: Ensure in the Permissions for the network share, that Guest is included, since it's no longer part of the Everyone group.
7. Use regedit to go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System and create or modify the value of LocalAccountTokenFilterPolicy (32-bit dword) to 1, so the remote logon token will not be filtered (see here).

On the machine where you shared the folder, open the command prompt or type CMD in run (to open RUN in Windows use Key+R). Then type ipconfig (followed by enter) so you will get the IP-Address of that machine. Now go to another PC and open the run again and type \\ followed by the found IP-Address and press enter.

For instance:

\\192.168.15.1 and press enter

Remember to replace 192.168.15.1 with the IP-Address you found on the main-machine.

Edit:

You do need to enable the firewall to let traffic for file-sharing through.
For ESET Smart Security you can look here for the settings to allow file-sharing etc.