server reboot unexpectedly

Hi,

I have SBS 2008 on HP Proliant DL 320 G6. The server reboot unexpectedly this morning and I got the message below:

Problem signature:
  Problem Event Name:    BlueScreen
  OS Version:    6.0.6002.2.2.0.305.9
  Locale ID:    1033

Additional information about the problem:
  BCCode:    50
  BCP1:    FFFFFA804B473630
  BCP2:    0000000000000000
  BCP3:    FFFFFA6003525F59
  BCP4:    0000000000000005
  OS Version:    6_0_6002
  Service Pack:    2_0
  Product:    305_2

Files that help describe the problem:
  C:\Windows\Minidump\Mini081913-01.dmp
  C:\Users\administrator.IZLAW\AppData\Local\Temp\3\WER-9453473-0.sysdata.xml
  C:\Users\administrator.IZLAW\AppData\Local\Temp\3\WERD413.tmp.version.txt

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Please help! What does the error mean? What should I do next?

Thanks in advance!

Grace