So I've just had to exchange my ASUS motherboard for a comparable MSI. However, my existing windows installation won't boot now. If I reinstall windows over the existing installation, will it retain all my applications, drivers, registry settings, etc. or am I going to have to reinstall everything? Thanks!

STOP! If the reason that it won't boot is because the HAL (hardware abstraction layer) is too far off then there are ways to fix just that I believe. Search the MS site for how to change hal. Now if it doesn't boot for other reasons then you will need to post more info. I suspect that windows doesn't like one of two things. Either the last setup used too different of devices or your boot/bios setup has somehow not allowed the correct. ?? dunno

Sometimes this will work. How to do a system repair.--Boot from the xp cd and go past the recovery console to the install menu. Select repair the existing installation. You won't lose any data except the xp updates. Unless you have a slipstream sp1 cd you will have to d/l sp1 and all subsequent updates. You MUST have at least SP1 installed and the updates for security reasons. Be sure the firewall and A/V is active before going online as you will be susceptible to sasser and msblaster. If you don't want SP2 go to autopatcher.com and d/l SP1 and subsequent updates. http://computervitals.com/

Hello. You do not lose anything except a bit of a time to re-install Windows over itself. A dirty install. If things do not run properly, then a reformat is in order. I suggest you should back up wpa.dbl and wpa.bak files in System32 directory. After re-install, put these files back in system32 directory in safe mode. This may save you a re-activation. Though I am not sure it works after the M/B change. Regards suatcini

I wish you had read this before you actually changed the mobo... Change Motherboard and Save Windows i_XpUser