I have a compaq server running Windows NT Server SP6. Along with being the central location for our main applications it is also our domain controller. A while ago a problem began where I would start getting calls from employees with a range of problems but the bottom line of all the problems is connectivity. Whether it was a remote database not loading or not being able to log into a centrally located version control program or unable to access shared resources on another computer. Clicking on various pc's in Network Neighborhood would result in Access Denied on some.. others would continue to function. Rebooting the server solves the problem.. for a while. It has happened at intervals anywhere from weeks apart up to twice in the same day. I have no idea what it could be or even what to look for. I would like to switch over to another computer I have available with Windows 2003 Server installed on it that I could turn into a domain controller but I am really dreading what will happen when I take the NT domain controller offline.
So I guess my problem/question is twofold.
1. Any ideas on what I can check that might be causing the domain to crumble until I reboot the controller again?
2. Should I write down all the groups, computers and users and their permissions from the NT controller and manually enter them all into the new computer before plugging it into our network? Or is there a better way to switch from an NT domain controller to a 2003 controller. (I don't think the NT controller can be upgraded - NT partition, no memory, slow, and just too old)

Thanks,
Robb