I can't remember... do I need to reformat my hard drives if I install a new mobo... I didn't think I did before but its been so long since I did... thx folks for any help.. later

Generally speaking...

You should not have to if you are running Windows 2000 or XP. These OS's are good at discovering changes and ensure you have compatible drivers.

It has been my experience with Windows 9x/ME, that you need to reformat the system drive and re-install the OS in order to have a stable/reliable system.

From what I have found.

If you change your Make AND OR Model of your processor. You will have to REFORMAT!

I disagree that you have to reformat. There is a fairly strong probabilty that you will not be able to boot after making the change because the old hardware is no longer found and the new hardware not immediately recognized.

The first thing is to boot to Safe Mode and install any new drivers. If that doesn't work, you might need to reinstall Windows, by booting to the CD.

Before you install the new mobo, make sure the ide controller is the windows standard one, and not a specific driver. That is the only problem I have ever had in changing motherboards on existing installations. Using the standard IDE controller driver, you should be able to boot and then install the other drivers (possibly in safe mode as Scott suggests).