Question : SBS 2003 R2 Premium locks up randomly

Twice in the past couple weeks our server has simply become unresponsive.  The machine still has power (Case fans and power supply fans still spinning and cdrom drive will open). However, moving I cannot get anything to come up on the screen. I move the mouse, hit the keyboard and the screen just remains blank.  I usually notice this when internet connectivity drops out from client computers (and also connectivity to the exchange server).

There are no strange listings in the event logs.

I have been forced to manually reset the machine both times.  It is in the process of a reboot at this very moment.

Any ideas of what i could look for? whether it be hardware or software related.

Answer : SBS 2003 R2 Premium locks up randomly

I'd be shocked if IMF cause a crash.  How about previous crashes?  Any IMF errors?  

I would have to strongly look at the hardware.  Is it new?  Few things you can try -

Run Microsoft's memory diagnostics - http://oca.microsoft.com/en/windiag.asp
Remove some memory - if it happens again, put the memory you removed back, pull other memory
Remove a processor

Etc. . .  Try to eliminate different pieces of hardware to see if it helps.  If you have any diagnostics that came with the hardware, run them.