This may be a bit helpful. First, the total amount of users who cn access Access at the same time is 265. Realistically, it is about twice that amount. If you use it as a front end to SQL back end, it is way past that amount. But, I doubt we have anyone on here that has over 130 users and, in fact, probably no practice.
XP Pro limits in the incoming connections to 10 and XP Home limits it to 5. Vista is 10. It doesn't matter what the OS is that is connecting, only the one that has the database on it.
If you go with an NAS, you need to make sure that is not a problem. I believe that this one
http://www.snapserveronline.com/index.asp?PageAction=VIEWPROD&ProdID=80 would meet your needs. There are many. Buffalo makes a good one, but just make sure whichever one you use allows more than what you have. Sometimes even your networked printers, etc. can count.
If your database is on an XP Home Edition, I would first try switching it to a Pro edition or to Vista. Even if on XP Pro, it may be worth trying it on Vista or vice versa. If you can get close, it may work out as it is the number of connections at the same time.
