Windows 2003 Enterprise Server becomes unresponsive occasionally

We're experiencing issues with our Windows 2003 server, which runs SQL Server 2005 SP1. We notice that sometimes the entire server becomes unresponsive and I captured a screenshot of the task manager when this happened. I noticed that the processes are not displayed during this time and all of the memory information and handles disappear (as shown in the screenshot). Does anyone have any ideas as to what could be wrong with this sytem? I'm planning to take it down over the weekend to run Memtest86.

Screenshot: http://dl.dropbox.com/u/2058/windows_screenshot.png

The issue is resolved by a reboot, but I'd like to figure out the cause of this and get it fixed.

I also tried to run a ping when this occurred and I got the following error in the event log:

"Application popup: ping.exe - Application Error: The application failed to initialize properly (0xc0000142). Click on OK to terminate the application."

Thanks, Derek

Based on your answer and comments, I'm going to guess that you also had PAE running in conjunction with the /3GB switch, which would cause your system to seize up like 80 year old arthritic joints. You need to a) read up on PAE and /3GB and b) for the love of $DEITY, move to x64 architecture. I know the economy is tight, but if you're straining the server like this, it's time to move to post 2003 technology. Some links on /3GB and PAE:

Consequences of running 3GB and PAE together

Enable PAE in x86 32-bit Windows Server 2003 and 2000 to Use Large 4GB or More RAM Memory

Physical Address Extension

Driver may not be loaded with the /3GB switch

Kernel address space consequences of the /3GB switch

Myth: PAE increases the virtual address space beyond 4GB

How to monitor and troubleshoot the use of paged pool memory in Exchange Server 2003 or in Exchange 2000 Server

I would hazard that something is trying to reserve a large block of contiguous virtual memory addresses in the kernel address space, and the system is locking up at that point. The only way to check that is to run Poolmon and monitor the system.... but like I said, it may be worth your while to just buy new hardware and move to a x64 infrastructure.