if your replacing the mobo then i suggest you start off with a clean install of windows and then installing the drivers for that new system because it might not boot into windows using the install from your old system on that new system.
back up all your videos and old data onto DVDs or thumb drives... or even an external hard drive if you can, then reformat the hard drive. if you dont feel like doing all that you could just reinstall windows under a different folder than the "windows" folder and delete the old installation once you've booted from that version of windows.
If you want to keep all of your old software, here is a trick I learnt from Microsoft....
Begin the upgrade process while using your old motherboard, when it arrives to the first reboot, turn off the PC and switch out the mobo, once done, continue with the re-install.
If i was to get another hard drive, and i have 2 going in my computer do i need another windows or can u still access the storage without needing the other os
If i was to get another hard drive, and i have 2 going in my computer do i need another windows or can u still access the storage without needing the other os