How old is this Windows installation?

I’ve often been faced with this question when sitting at a client’s site and debating whether the quickest fix isn’t perhaps a reinstall of the OS. It always helps to know when the system was last (re)installed. Thanks to this blog (blog.dampee.be), I found the answer. (And as is usually the case I wasn’t even looking for this at the time).

There is a little command called sysinfo which is documented on Technet. Simply open a cmd prompt and run the command. Scroll back up and you should see the following lines: