Most install problems are due to broken installs, failed uninstalls, and
other debris buildup. See this tutorial for instructions on how to clean up
your system of this debris to allow proper install processes to occur.
http://www.vistax64.com/tutorials/87249-unable-install-latest-version-program-vista.html
For problems related to having the ability to modify files or folders see
the following. Even running as Administrator may leave you without
permissions to modify some files or folders, even ones that you have
downloaded and installed. To modify (copy, delete, rename) files or folders
you can take Ownership of (in your Username) and grant yourself Full Control
permissions of the files or folders in question described in the following
tutorial.
Another way to gain access to modify files and folders includes going to the
Start button, typing in Windows Explorer, right-clicking on this and
selecting Run As Administrator. You should then have "elevated privileges"
to do whatever you wish to files in Windows Explorer. There is also a
program called Unlocker that you can use to gain access to modify files and
folders (see link below).
http://www.vistax64.com/tutorials/67717-take-ownership-file.html
http://ccollomb.free.fr/unlocker/
