Logging on as administrator (the new administrator account), can you take ownership of the directories where the files that you can't access are located?
Right click the Directory - properties - security - advanced - take ownership. Change ownership to the new administrator.
You "should" then be able to access the files.
Assuming that you can, I would backup whatever you can/want/need and then trash the install, re-format and load from scratch. make sure you have a note of your hardware config, and have the correct drivers to hand.
SD