It's foolish to put to much trust into the System restore feature
Some days are crappier than others and I feel the need to vent and perhaps help others to avoid placing trust where it does not belong.
I finally came around to upgrading my Synaptic Touchpad drivers to allow me to scroll using the scroll buttons in Mozilla on my ASUS laptop. I had known for quite a while that it was indeed possible, I just never got around to it. I wish I hadn't.
The new driver seemed to install successfully, I was enthusiastic regarding the new configuration options available and everything worked fine until after the reboot. The new settings for the touchpad had vanished for no appearent reason and it was no longer possible to access the touchpad configuration. Having worked with computers long enough I chose to reboot again. Even though XP is usually remarkably stable and I have had it up and running for weeks, reboots still seem to have magical effects when you are in trouble.
The laptop was suddenly not able to boot successfully. Each try resulted in the crappy loading animation freezing. (I really must install bootskin sometime) Tried to shut it off for a while to no avail.
I was not really concerned at this point. I carried the belief that the system restore feature would solve my problems.
I booted into failsafe mode and ran the system restore feature. Chose the last working checkpoint (the day before).
All seemed to be working well and I rebooted.
Still stuck on the loading animation.
Booted into failsafe mode again and chose another older checkpoint.
Still stuck....
After testing about 10 checkpoints I concluded that the system restore feature did not do much for me.
Still not very concerned. My thoughts were that I could still do it the old fashion manual way.
Booted into failsafe mode. Uninstalled the driver. Everything seemed to work well (it is funny that everything always seem to be a success in XP).
Rebooted and... Ha! The moment of triumph! I finally reached the logon screen!
Choosing my regular account.
Typing my password... hm... nothing... odd... typing my password again... nope! My keyboard isn't working! Great!
Rebooting into failsafe mode... Keyboard still not working! I tell a short curse on the person that named the failsafe mode "failsafe", I tend to think that a working keyboard driver should be a necessity for calling the mode "failsafe".
Being somewhat security conscious I had naturally password protected all local accounts besides the Guest account... Using the Guest account I logged into XP (sighing with relief as XP had recognized my USB wheelmouse so I could at least point and click). The device manager could at least confirm that the synaptic touchpad and the keyboard shared a driver and that both were not working. Unfortunately the guest account only had viewing permissions and I could not reinstall any of the drivers needed.
By then I started to suspect that there might be a hardware problem.
Booting Knoppix. (which is a really cool Linux live CD that I use to when helping family and friends with their computer problems. When it is difficult to discern if a problem is related to software or to hardware a quick boot to Linux usually helps to determine if they should replace their network card or if Windows is cranky)
Both keyboard and touchpad worked as well as usual in Knoppix.
At that point in time I was more than a little concerned. Reinstalling all software again would involve quite a lot of time. Time that I would rather spend on more interesting things than watching progress indicators and rebooting XP five hundred times. Don't get me started on XP reboots btw, I upgrade quite a lot of software on my Red Hat Linux 9 without ever having to reboot (exempting kernel upgrades).
I was already making up plans to backup all my files from my laptop to my stationary computer using Knoppix (thank god for it being able to read NTFS volumes) and performing a full restore when I realized that I hadn't eaten in hours. When enjoying Bouillabaise leftovers from yesterday simple solution to my problem struck me. They say that eating fish makes you intelligent but this was ridiculous. 
I booted my laptop into the Guest account.
Launched the "Help and Support"-application and Notepad.
I cut and pasted my admin account name and admin account password into notepad, letter by letter.
From notepad I could then cut and paste the account name and password into the RunAs dialogue, allowing me to access the device manager as administrator. Five seconds later the problem was solved... Sometimes the simple solutions are best but are hard to think of as they seem to primitive.
I could even install the synaptics driver and it works well now. Wonder what went wrong last time?
So what have I learned? What should I pass on?
1) As usual, BACKUP, BACKUP, BACKUP and backup more often. At the very least - backup sensitive data that can not be replaced later on.
2) System restore is not to be relied upon. I have spoken to some friends about this feature as well and most of them had experienced similar results.
3) Think twice about password protecting your accounts. My Guest account will always be enabled and not password protected. That is for sure. Even though there are security concerns involved. That said most people do not encrypt their data anyway making it easily accessible from, e.g. Knoppix. What stationary computer does not allow for bootable CD:s today?
4) RunAs is a nifty feature, in Linux su is used almost daily but I hardly never use Run As. Probably because I run as administrator more often than I should.
5) Knoppix is a really cool Linux distribution.
All this being said I usually get along with XP very well. Even though Stardock software (and the lack of a driver for my laptop WLAN card, cmon DLink) are the primary considerations that keep me from removing XP and replacing it with Debian, I still find it easy to use and stable.