windows not shutting down correctly

i keep getting error message "windows recovered from an unexpected shutdown" details below

Problem signature:
Problem Event Name: BlueScreen
OS Version: 6.1.7601.2.1.0.256.48
Locale ID: 1033

Additional information about the problem:
BCCode: 7a
BCP1: FFFFF6FC50083D48
BCP2: FFFFFFFFC000000E
BCP3: 000000000EDD0880
BCP4: FFFFF8A0107A9880
OS Version: 6_1_7601
Service Pack: 1_0
Product: 256_1