15" MacBook Pro to 27" iMac monitor Can I hook up my 15" macbook Pro thunderbolt to my 27" iMac thunderbolt, and operate the MacBook pro in Windows 7 in order to have a large monitor to run AutoCad?

Both computers are running OSX Yosemite and Bootcamp Windows 7.
According to Target Display Mode: Frequently Asked Questions (FAQ), you can't do it.

8. Can I use TDM in Boot Camp?
Target Display Mode is not supported under Boot Camp.