>>>Are you able to run SQL Server? What does version say and information about current service pack?
>>>
>>>I also suggest to post this question here
>>>http://social.msdn.microsoft.com/Forums/en-US/sqlsetupandupgrade/threads
>>>
>>>You most likely will get a better answer if you post there.
>>
>>Yes, SQL runs and I shows version 10.0.5500.0, which indicates SP3. It may be true, however, that the version indicator was set before the installation was complete. So now I cant verify complete successful installation, and I cant back-out unless I completely uninstall. I need to solve this before I try updating the production servers.
>
>The error logs say that SSIS could not be started because access is denied, but SSIS is not installed.

I think chances are that this server is OK and has SP3 installed successfully. To be 100% sure I can only repeat my original suggestion of a better forum. If you post there, can you post here a link, please?

The reason I suggest that forum as several MS people who work on Setup and Upgrade monitor that forum and also several SQL Server MVPs.

A while ago when I was having troubles installing SQL Server 2012 I worked closely with one of these MS people and he was finally able to give me a path to follow as well as find a bug in original installation package (which I hope is resolved now).