Yes, it would make a difference. You must use the same version to run system file checker. And it does sound as though you have a number of issues. Tell you what, before you reformat why not try a repair install. Create an XP SP3 disc of you don't have one (you can use nlite to slipstream), boot to it, and choose the SECOND repair option. XP will install on top of itself. Either this will fix your problems or it won't. You can always reformat later.
And re the sound issue - do you want to provide some background on that?