For the second time now, the PC automatically shut down and rebooted. Event viewer has the following info

Error Code 100000d1, parameter1 00000000 paramater2 00000002 parameter 3 0000001, parametner4 ba43d2b5


Is my memory faulty?

Hard to say what it is. The error code you posted is merely telling you there was a memory dump.
First thing to do is remove one module and reboot. Does it boot.
Change memory modules and reboot again. Which one works. If both work, it is not memory, but more likely a hard drive failure or glitch.

Thanks for your reply.

Yes the computer works fine now. But within a month this has only happened twice. All of the sudden the PC shutsdown and reboots without warning. Is there some sort of logging I can setup to monitor and find out whats wrong?