System file corruption-alternatives to erase&install?

Question

To make a long story short(er) I restored from (SuperDuper) backup after the HD failed and Apple gave me a new one. Then problems occurred with the system being slow (hesitating a lot) and having trouble connecting via wireless and finally not connecting at all, and then the machine ended up in "limbo" (according to the Mac Genius.) Now I've been told to erase and install, but I'm reluctant... There's a years worth of tweaks, updates, and installs on my MacBook! (After all, that's why I was so fervent about backing up...) And Boot Camp too.*)
Evidently "some" corrupt system files made their way into my backup before the old drive failed. (There was no warning; one day it was just gone.)
My question is, is there a way to figure out/diagnose which system files are corrupt and to replace only those? Or, alternatively, is there a way to "erase and install" only the system? Please forgive my "lack of Mac," I come from many years with Windows.
*)I'm assuming I can use Winclone to restore Windows (if I really have to erase the drive) once I repartition using Boot Camp. Um, all I have to do is remember how big I made that partition...

Answer 1

I suggest that you start with an Archive and Install (checking the box to preserve settings). The last time I did this was in an upgrade from 10.2 to 10.3 on our little iMac G3, and after it finished, everything was just exactly the same as it had been under 10.2, except for one thing: those little pictures were gone by the users' names on the login screen (it was trivial to reconnect those pictures with the names). So I would try that, and see if your issues are fixed. If they are not, then there is another step you can take, which is to delete your preference files that are associated with the problem (i.e. wireless, airport). and if these things are not effective, then I would proceed with the full erase and install. I haven't done the Archive and Install with Tiger but I don't think it gives you a lot of options about what setting to save ... I think it's either all or none.
By the way, before doing any of these things, you should make at least one complete backup or clone of your entire disk.
Also, before doing Archive & Install or Erase & Install, create a new user and login as that user to see if the problem goes away. If it does, then there is not much point in doing a new system installation because the problem would have been pinpointed to your local user files/preferences, not the system-wide software.
I am not surprised that the Apple Genius suggested Erase/Install versus Archive/Install. The Erase/Install is guaranteed to fix any software issue, so the Genius won't need to deal with you in a follow up anymore. They have people lined up and want to just get you on your way, even though it might cause you a lot of work to recover all your settings and installed software (that's your time, not his). The Archive/Install is also highly likely to fix almost all software problems, but if it's something corrupted in your user settings, then it might not, in which case you'll be back and he'll have to deal with you. So he's suggesting killing a fly on a window with a sledgehammer, when maybe a flyswatter would work just as well (and cause less collateral damage to your house). I understand the motivations of a busy Apple Genius, but from your point of view, it would be better to try the other things before finally going to the erase and install.
Remember to do that backup before trying any of these things.
In general Macs do not need to have system software reinstalled. In fact I have never had to do it as a repair/diagnostic step on any of my machines using Mac OS X (except that one Archive and Install I did, but that was on a healthy system to go from 10.2 to 10.3).