Processor and RAM upgrades should have no effect on Windows but each motherboard has different drivers which must be installed for stable performance. I have swapped motherboards and installed the drivers for the new board without reinstalling Windows on several occasions and it has worked ok but at other times it has been a no go, all depends on the boards involved. As a general rule I believe that it is a better idea to do a format and clean install but if you decide not to go this way, before you swap boards first back up all your data then disable all programs which load at startup, also any screensaver, scheduling and power management etc. On your first boot Windows will find a multitude of new devices, just click OK if and when necessary, insert your Windows CD if it asks for it and follow the prompts. You may have to do several restarts. When (and if) you can boot cleanly install the drivers for the new board immediately. Best of luck.