Vista - Keyboard and mouse (both PS/2) stop working when Vista64 sp2 loads.

I recently broke down and decided to try Vista with an open mind (and I have to say, so far it's not quite as bad as I remembered). The problem is, I'm finding it to be very unstable and "flaky". I've been working on a dual boot environment today consisting of XP professional x64 which all ready on system, and I partitioned off 100 Gb from my primary hard drive for Vista Ultimate x64 (installed behind XP; which I know isn't ideal but I didn't feel like completely redoing my system today and putting two OS's on).

Anyway, let's cut to the chase...

I've been struggling with instability all day and weird occurances that I'm not used to. Pretty much 50% of the updates i applied led to some hassle which I had to go back and undo. The final straw (which brought me here) was when I installed service pack 2... It seemed to install just fine, but when it rebooted and came back up I had no mouse, keyboard, and oddly enough wallpaper which is where I stand now...

From there I tried a few things. First I tried to repair the boot sequence, no luck. Then I tried to do a system restore from the boot/install disc but apparently my restore points were destroyed as well. I tried to manually install some keyboard/mouse drivers but I didn't really know what I was doing and as such, it didn't work either. I triple checked the bios, and checked with my XP environment and so it's not hardware or the bios, it's limited strictly to the Vista boot sequence. If I boot with a recovery disc or into XP, both the mouse and keyboard work fine (and they work even passed the "safe-mode" menus)...

My questions are these:
- Is it possible to somehow create a bootable rollback disc so I can try going back to service pack 1?
- Is there some way I'm not thinking of to uninstall service pack 2 from the shell?
- Is there someone to patch the driver files (I'm assuming this has to do with drivers) at least so I can log in and start working on it from within Vista?
- Anyone have any ideas that I'm not thinking of?

Thanks in advance for the help, and I'm sure I left some information out so I'll appologize now.

Every time you boot XP, your Vista system restore points are deleted. Try running sfc /scannow at a command prompt, and then scanning for rubbishware with malwarebytes and superantispyware.

Also check device manager for any old drivers highlighted by a yellow exclamation point, and update your drivers as well. Finally run the memory diagnostic and check your hard drive fore errors with chkdsk via properties of your hard drive, tools, check now and tick both boxes and apply. Reboot.

At the end run glary utilities, and all of the clean up and repair options in the modules tab.