True workstation and server boards tend to just have higher quality parts and often things you would expect to see such boards. Server boards might have dual power plugs so you can hook up backup PSUs. Or they will have built in RAID controllers, dual NICs, etc. Workstation boards are similar, though usually its just beefier parts as opposed to the dual parts. To my knowledge you can install any version of windows on any board, as long as there is a hope for driver support. Check your board for drivers.
The only limitation you get with windows is the RAM and CPU Sockets.
With Windows 7 you are limited to the following RAM limits
8 GB Ram 1 CPU Socket on Starter & Home Basic
16GB Ram 1 CPU Socket on Home Premium
192GB Ram 2 CPU Socket on Professional, Enterprise and Ultimate
While 192GB may sound quite a bit for single socket home systems, a high end workstation or server can have 512GB to 4TB of ram and 2 to 8 CPU sockets.