Uptime is incorrect.

[townsbg]

On my Vista virtual machine today I looked at my uptime on task manager and it says 239 days indicating that I last shut down my virtual machine on 5/3. I knew that this wasn't correct so I ran systeminfo and it shows last boot at 10/16, 73 days ago, which is about the last time I backed up the virtual machine and I know that I shut it down then. Net stats workstation also shows 10/16 although a different time. I googled it and all I found was about 10 and the reasoning was that 10 hibernates by default on shutdown, however Vista does not. Why the 166 day discrepancy?