Bert, I agree that his problem is most likely a networking issue, not an AC issue and not a hardware issue. The real bugger will be in finding the issue. Since it sounds like he's using a P2P, this could be the source of problems. If he is using Vista Home, this could very well be the problem. As you know, I once ran my P2P on XP Home and it worked fine for a while before everything got screwed up. My problems resolved w/ addition of my server and upgrading my client OS's w/ Vista Business.
On Vista options however, it should not be as complicated as it would seem. There is Vista Home Premium and Home Basic. Neither of these are options for the small business user, as these are HOME editions. Like Bert has said to me when I ran XP Home in my office, "What part of HOME don't you understand?" Then, you have Busniness-N and Enterprise. Neither of these are options because Business-N is only for Europeans and Enterprise is designed for complex IT setups and is for large businesses.
Therefore, that leaves Vista Ultimate and Vista Business. Business does what it says, it is set up for Networking, P2P or Server/Client setups. Ultimate supposedly has it all. The only choice should be "Do I buy Business or Ultimate?" So Bert, you could ask a similar question that you posed about XP Home, "What part of BUSINESS don't you understand?" If an AC user is going to use Vista, they need to ENSURE that it is either Vista Business or Ultimate editions.
