I have seen several requests from people requesting assistance with retrieving Windows Product/License key in preparation for a re-install.
I have posted a helpful utility here: http://gallery.technet.microsoft.com/Obtain-License-Information-5cc6a5e5#content
If you find my information useful, please rate it. :-)
Another useful utility is ProduKey, from Nirsoft: it can be downloaded for free from http://www.nirsoft.net/utils/product_cd_key_viewer.html.
Also very useful is Belarc Advisor - http://www.belarc.com/free_download.html - free to personal users. This analyses and reports everything you ever needed to know about your computer. Not just product Keys for ALL installed applications, but hardware details, serial numbers and lots more. A truly amazing and comprehensive tool.