The reason you are getting permission denied is because the permissions are based on SID's (the SID's get translated to user names and groups by the OS). When you re-installed windows on the other hd, the SIDs that translate to Administrator, are different than what's working on your original drive. What you have to do is go to the security tab for the folder you want to access (or the entire drive letter), click Advanced, click the Owner tab, select Administrators (or your user name if you want to) from the list and check the box to replace owner on subfolders the click OK. This will replace the owner of the directory and all files and subfolders to your current user (or the Administrators group). After you do this, you will need to go add the proper permissions for your user account (or the administrators group or the everyone group) to the folder.
After this, you should have no problem accessing your files. If you do, I'm sure you'll let us know
Enjoy