Better rent your wife a laptop for two weeks so you can do all you need with this PC and copy the files she updated from the laptop to the PC when you're ready after that 2 weeks and all is working perfectly.
My computer has 2 hard drives, 1 x 500GB, 1 x 40GB. The 500GB has the OS, programs and all my data and I wish to do a fresh install, but my wife needs the computer constantly. As the fresh install would take some time (I only have a spare hour a day) , can I install the same copy of the OS onto the 40GB HD, install the programs and data. Then once finished create an image of the fresh install and restore this to the 500GB using image backup software? If so how do I boot between the drives?