Hard to clarify what the areas to look at knowing more about the symptoms. IF things “hang” then it could be a highly utilized application driver or agent or just pertaining to upcoming hardware failure on memory, hard drive, etc. I would schedule a maintenance window on this server and run a “vendor” hardware diagnostics to rule out the hardware layer as the problem. If that is all clear, then I would review the event logs to pinpoint where the problem is. If you see things in “system”, I would lean towads windows and drivers issues. If you see things in “application”, then it could be a loaded application or such on the system.