Hello Trish, glad to hear you can carry on working. I thought the update might of made a mess of your system, the system restore you had already done may have removed the update ( officially! ).
After altering the start value in your registry I was going to suggest using a registry cleaner, next time you run a disk check have a look at the comments after each stage and it will tell you if it fixed any errors and how many it fixed.
It's up to you if you want to try a registry cleaner considering that so far everything is working again, but I will give you a word of warning, if you do use one don't always just clean everything that it has found as sometimes there can be another explanation as to why the registry cleaner has flagged an entry. Inexperience could lead you to deleting something that you need.
However it does also tidy up your registry and make you PC run that little bit more smoothly especially after a failed installation. If you decide to try one you can just use a trial version that won't let you delete everything but it will show you all of the obsolete entries and help you in making a decision on wether you should use a cleaner or not.
And you could always get back to us at Syschat for some more friendly advise!
Finally, make sure you are running a Defrag at least once a week, and a Disk Check at least once a month to keep on top of your PC.
P.S. I've just started to learn some .asp for web design, can't get some code to work. Do you know anything about IIS.7.0 and 'Select Case'? It doesn't want to work!