I don't know how to fix your mouse (or how it was automatically fixed), but I just want to help you out with some stuff that you seem confused about.
1) There was no problem with having a "486" kernel installed. Oftentimes, kernels are named i386, i486, i686, etc, basically just to let you know the earliest platform it was made for. They are all examples of 32-bit kernels, and have absolutely nothing to do with number of processors or cores. For example, I have an old Pentium 4 w/ HT Thinkpad laying around somewhere running an old 2.6 era i386 kernel, and multicore processing works just fine on it... An i386 kernel would have ran just fine on a Core i7, for example, just as it would (theoretically) run fine on an old 80386 system. An i486 kernel would have ran just fine on a Core i7, or an old 80486 system, but NOT on an old 80386 system... etc...
2) i686 PAE has nothing to do with multiple processors or cores... PAE is simply Physical Address Extension. A PAE kernel allows your system to use more than ~3 gigs of ram on a 32-bit system. A standard 32-bit system will only address around 3-4GB or RAM... PAE adds support for larger amounts of RAM (up to 64GB) without installing a 64-bit kernel.
3) For performance reasons, if you want to address more than 4GB of RAM, and you have a 64-bit processor (you probably do... I can't think of any current multicore processors that aren't 64-bit), you should definitely install an x86-64 (or amd64, depending on what your distro calls it) kernel. IMPORTANT NOTE: IA-64 is NOT what you are looking for... it's a 64-bit kernel specifically for Itanium 64-bit servers... An amd64 kernel will outperform a 32-bit kernel on similar hardware. It also allows an insane amount (more than you'll ever need) of RAM to be addressed. Don't let the amd64 name fool you, it is the same kernel that you'd want to install on an Intel 64-bit system too...http://www.phoronix.com/scan.php?page=a ... ae64&num=1
i686-PAE doesn't have anything to do with multicore processors.
If you really wanted to maximize performance, you should install an x86_64 kernel instead, as a 32-bit PAE kernel will probably not net you any type of performance boost.
x86_64 (amd64) > 32-bit PAE (i686-PAE) > 32-bit (i386, i486, i686, etc...)
I think you might be getting SMP confused with PAE...