I have a client with a chiropractic practice management system called InPhase. We installed 2 Win7 PRO x64 PCs. These new PCs frequently hang when accessing the data in an MDB file which sits on a XP Pro PC. Other PCs running XP have no problem when accessing the same file using the same application. All are set for multiuser access in the application. What could be causing this issue? Usually the new PCs hang for about 10-15 seconds, but sometimes they never come back.