Latitude E6440 Reboot on Sleep

Hi I have a Latitude E6440 running Windows 7 64-bit. Ever since I bought it, I was not able to put the machine into hibernation or put it to sleep. When putting it to sleep it simply reboots and I get a windows error message "Windows has recovered from an unexpected shutdown." It lists the values below under "Problem details". Problem signature: Problem Event Name: BlueScreen OS Version: 6.1.7601.2.1.0.256.48 Locale ID: 2057 Additional information about the problem: BCCode: 100000ea BCP1: FFFFFA80069F5040 BCP2: 0000000000000000 BCP3: 0000000000000000 BCP4: 0000000000000000 OS Version: 6_1_7601 Service Pack: 1_0 Product: 256_1 Due to this I always have to shutdown my laptop. Can't just put is to sleep. Any help? Nerdnum