We recently joined a company to a domain, at first everything was smooth, but a few days later people started experiencing random lock ups. So far three are having the issue locally, and at least one is having the issue remotely when they log into the terminal server. There seems to be no correlation between the lock ups, and no commonality, it just occurs at random, there's no event log entry either, other than an entry stating that the computer shut down unexpectedly.
All the Client machines are running either Windows 7 pro or Windows Vista Business, except one or two older machines running XP Pro (which aren't locking up). There is also one Windows Vista Home, but that one shouldn't affect anything since its obviously not joined to the domain.
The server is running Small Business Server 2011 and is acting currently as a Domain Controller, File server, Exchange Server, Quickbooks Server, and soon a terminal server once we get it upgraded with a bit more ram.
At first I thought it might be the fact that their Quickbooks file is far beyond recommended size, over 30 gigs, but people's computers are locking up even when they aren't in Quickbooks so it rules that out.
One more thing that may be noteworthy is the fact the server, at the moment, is operating at nearly full capacity as far as the RAM goes, currently it has only 8 gigs and its using about 95 percent of it, hopefully by the end of the week we'll have it up to 48 or 64 gigs.
Thanks in advance for your help.