Hi Travis,
Thank you for reaching to us on Microsoft Community.
From the issue description, it looks like you are facing issues with accessing or sharing files on HomeGroup on Windows 8 computer.
To help you suggest steps to resolve the issue, I would appreciate if you could answer the following questions:
1. Did the Windows 7 computer joined HomeGroup successfully?
2. Do you receive any error message or error code?
Let’s follow these methods to fix the issue:
Method 1: You may run the HomeGroup troubleshooter and check if the issue persists.
HomeGroup problems in Windows
http://windows.microsoft.com/en-US/windows-8/homegroup-problems-in-windows
Method 2: You may follow steps from the article mentioned below and check.
Why can't I connect to other PCs?
http://windows.microsoft.com/en-US/windows-8/cant-connect-other-pcs
You may also refer to the following article for more information:
Share files and folders on a network or a shared PC
http://windows.microsoft.com/en-US/windows-8/share-files-folders
Hope this information helps. If you need any assistance on Windows please revert back will be happy to help you.