Ideally you want to reinstall windows when you change motherboards.
You may need to get another window licence if yours is an OEM licence. If it is a Windows 8 OEM, then you can reuse the product key.
What, exactly, are you planning to replace, and with what.
i waht to get a MSI ATX DDR3 2600 LGA 1150 Motherboards Z97 GAMING 5 or a ASUS Z97-A ATX DDR3 2600 LGA 1150 Motherboards Z97-A wath a Intel Core i5-4690K Processor 3.5 GHz LGA 1150 BX80646I54690K i what to keep me old hard drive wath it