External hard drive problem. Some folders locked, 150gb missing

[cmf21]

My father wanted to format his computer. Before doing so, he made an exact copy on his external drive and made sure everything was there. He then formats his computer reinstalls windows and some programs. He gets to the point where he wants to copy some documents and stuff back over but 150gb seems to be missing and some folders aren't accessable. Says you don't have permission, acess denied, etc. Can't find a solution on the internet that works. He's using XP Home. Read somewhere about turning off Simple File Sharing, or changing permissions since id's have changed but he doesn't have those tabs or options. Any solutions? Are the files still but don't get reported?

 

[cmf21]

Think I almost got it figured out but still confused. I can get into safe mode and choose admin instead of the other account. I take ownership of the drive and all contents. I can now see all the files and folders on the disk. Everything is there. When I restart windows in normal mode, I don't have access again. I don't know if I have to log in as admin (doesn't ask, logs in under the normal account). Do I need to set up user accounts differently?

 

[cmf21]

Fixed the stupid thing. Had to log into the other account in safe mode and take ownership as well and now I can see everything. What a pain.