Answer is no. When you install a new Operating System (OS) it sets the System Restore points for when that OS got installed. You shouldn't have any Restore points older then the current OS, then again you shouldn't have any according to some since it's mostly just a resource hog and does more bad then good most times. Also depending on how long that OS has been installed the restore points won't go far enough back to even worry about that since Restore deletes old restore points.
That depends on what you have them set to. It's easy to go back a month or more if you've never changed the default settings.
As to more bad than good system restore actually works quite well although it is sometimes used as a hiding spot for viruses, spybots and/or trojans because the OS won't let you manually search them out when they are hiding there (restore points are protected system files). Fortunately, those that hide there are easy to get rid of by simply deleting all restore points then re-booting.
But yes, the answer is no. You can't back past the OS instal point.
