MySQL Installation Error 1045

Hi all I am trying to reinstall MySQL and have been hit by the dreaded connection error 1045.
I have found various threads on this subject but no solutions that work for me, I feel that there are a number of possibile causes for this problem on my computer no least the Windows security which covers a number of directorys and their permissions.
The OS is Windows Vista Business 64bit which appears to have multiple levels of Administrator in use. I am logged on as Administrator but have not got permission to write or edit files in the directories wwwroot or Program File or their subdirectories. I can move a file from another directory into one of these, if I get permission from another level of Administrator, the screen darkens and a dialog box opens asking if this action is OK? I say yes and off it goes!
The error message is in two parts the first is about opening the TCP port 3306, this should not be an issue for me because I can see that it is open and allocated to MySQL Server in my Firewall Exceptions.
The second part speaks about the data directory not being removed on uninstallation of the MySQL software.
Can anyone tell me where to look for this directory so that I can delete it?

Any other comments on how I should get round this problem will be appreciated.

Thanks in anticipation.