What is the "Homegroup" (i.e. Network Name)? I hope it's not "HOMEGROUP" (the default) otherwise it won't work. You MUST pick another name... "HOMEGROUP" is just the example name. For example, I chose "ACTIONTEC" for my Network name - our present router so I can never forget it.
Also, if even ONE CHARACTER is off on either computer's Network Group "Homegroup" name field, they WON'T be able to be linked. Period. So make SURE you type them both exactly the same.
That was my problem when I was Networking our XP Home Premium, Vista Home Premium and my 7 Ultimate x64 systems. It's all to do with the "HOMEGROUP" name.
You also SHOULD NOT name your computers the same on the network, they MUST also be UNIQUE. I am not talking about your UserName here, I'm talking about each computer's IDENTIFIER name, which should be in the same screen as the "HOMEGROUP" settings.
Again, for example mine are: "MASTER" (XP - our "Network Server" Desktop) "COBALT" (7 x64) and "SAM" (Vista).
If none of these are the issue, then... I really don't know what to tell you. I think Baddcog has a point though... you shouldn't have disabled anything in the OS. Services are important and unless you know EXACTLY what they do and what they are for, you shouldn't mess around with them. Unless they are actually in use by something, they DON'T use any resources. If they ARE being used, they ARE necessary and should not be messed with.
With that said, the next step would be re-enabling them ALL, and then IF the network miraculously starts working at this point, go in and disable them again individually, while also checking the network each and every time you do this to rule out which ones are necessary.
Good luck and I hope you get it working!