When trying to reinstall my files from itunes back up on new hard drive It states that I do not have permissions to those files & access is denied

I backed up my itunes folder to my external hard drive.I then replaced my hard drive in my pc & installed windows 7 64 bit on the new hard drive. I reinstalled iTunes & and logged in & all my cloud purchases apperared. All my other music on the external hard drive is my problem. When I just try to open the file it states that I don't currently have permission to access this folder. I have tried to to take possesion of it & change the permissions but it keeps saying access is denied. I tried to drag it in to iTunes but it says I do not have permission. I am pulling my hair here because I have a lot of music that I cannot get to. I am so afraid that I am going to lose it all, I need help!! Please!!!!