You should probably change some settings in the network and sharing center's "advanced sharing settings" if you haven't done so already.
To do this:
1. look at the main page of the network and sharing center. Take note of the type of network your network card is using I.E. home/work or public.
2. click "change advanced sharing settings" from the left bar.
3. Expand the submenu of the network type you noted in step 1.
4. set network discovery -on. File and printer sharing - on.
5. If you want automatic full access to the public folders (located in c:\users\public) for anyone, turn that on.
6. I personally use 128 bit encryption but unless you have some specific security concerns this shouldn't matter. (but I would make sure they are both set to the same)
7. I've always used password protection, if you try without and run into complications, someone else will have to help.
8. Homegroup connections are lame in my opinion, but I've never truly intended to use them as I don't see any advantage. You can leave this on default it shouldn't matter anyway if you don't then go set it up.
Ultimately depending on your choice of sharing method you don't have to do all the things above, but perhaps for what you've already done "file and printer sharing" is turned off?
good luck.
So I played around with the steps above. When I turn on Password Protection I cannot see any shared files or folders between the two machines. When I turn off Password Protection I can see shared folders, but when I try to access them I get the Windows cannot access \\ComputerName's Files error.
I created a shared folder in My Documents and gave full permission settings, but that doesn't seem to do it. There has to be permission settings somewhere that I'm missing, but I'm just not sure where they are?