It's happened 4 times over the course of about 3 months, and I can't seem to notice a pattern. This is the error code I'm getting when it starts back up having "recovered from a serious error":
BCCode : 1000007e BCP1 : C0000005 BCP2 : B989C8DA BCP3 : BA507C40
BCP4 : BA50793C OSVer : 5_1_2600 SP : 3_0 Product : 256_1
BCCode : 1000007e BCP1 : C0000005 BCP2 : B989C8DA BCP3 : BA507C40
BCP4 : BA50793C OSVer : 5_1_2600 SP : 3_0 Product : 256_1