|When encountering problems with Windows update, I recommend manually updating one update at a time, this way if one fails, you know which one it is and you can install all others while looking for a resolution.|
You may have more restore points than you think you do. Unless you changed the default 12% of disk size to something significantly lower (or you have a very small disk), you will probably find that you just need to check the small box marked "Show More Restore Points" and you will see them.
If your machine ever had Norton or McAfee, even if it was a trial version, it may still have bits of it left behind that can cause problems. If this is the case, download the appropriate uninstaller from their website to remove the remainders of the program completely.
If you manually do an update and it fails, you are given an option to find a solution right on the page that said it failed. This option starts out with simple possibilities, but if they fail, there are more options. Eventually, if you are persistent you will get an option that will let you repair the Windows Update itself (5 or more levels into it). This should be able to fix just about anything.
If all else fails, consider backing up your files and reinstalling or doing a factory restore and starting over. If you do this, perform manual Windows Updates repeatedly until all updates are in, then install your antivirus program, and everything else.
You have to be a little bit crazy to keep you from going insane.