Hi Yorkie 1
Whatever type of motherboard you replace your old one with, you shouldn't need to reinstall Windows, as the operating system "lives" on your hard drive, not your m/b.
The Soltek m/b you mention is at least 2.5 years old and I would not expect you to be able to find an exact replacement easily. Best to decide what main features (processor, expansion cards etc.) you need to accomodate and buy a more recent m/b based on that.