You notice that your server has little or no RAM available.
You are using VM Ware or Hyper-V
When looking in Task Manager, adding up the RAM used by the visible processes does not correctly match the amount of RAM in use.
For example, you have 16gig RAM, 14gig is showing as being in use, but when looking at the individual processes, you do not see 14gig in use by the processes.
This is a known problem caused by a misconfiguration of the virtual machines memory.
You can confirm that this is the case by using RAMMAP from Sysinternals - http://live.sysinternals.com/rammap.exe
You can see that "Driver Locked" is consuming a much larger chunk of RAM that it should.
RESOLUTION / WORKAROUND
Follow the instructions for the VM that you are using
VM WARE: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1003470