Does anyone have any sugegstion how I can proceed to gain access to my data? Help!!!
Firstly, if you have XP Home, you need to be in Safe Mode. If you have XP Pro you need to disable Simple File Sharing in the Folder view options.
Assuming you've tried that:
Does the security tab show up at the root of the drive? If so you should be able to take ownrship there and force all child directories to reset to inherited permissions.
If all else fails CACLS at the command line can probably fix it for you.