Cannot move some files from external HD after Windows reinstallation...

[GSDog]

I just formatted my HD and reinstalled Windows. I added my external HD after the reinstallation to copy all of my backed up data, which includes video files, etc. For some strange reason I can only move some of files but not others...
I can play audio files and move them to this HD from the external HD, but I cannot seem to move or play 99% of my .avi movie files and I can't move my Mozilla firefox bookmarks file, etc.

I didn't have this problem before I reinstalled Windows as I was playing a movie earlier today and it worked fine... It seems since I reinstalled Windows I cannot move or use certain files from external HD.
Here is a screenshot of when I try to play a movie;

http://img201.imageshack.us/img201/4730/wmperrorqh6.jpg

And when I try to move the file from the external HD to my laptop;

http://img248.imageshack.us/img248/3082/movingvideofilesgo2.jpg

What could cause this?

 

[GSDog]

I just tried the external HD on another computer and it had the same problem... so I don't think it is my computer afterall...

My external HD is encrypted with Truecrypt, so I don't know if that is causing it or not.

 

[GSDog]

I think I might have found the problem...

When I browse through the folders and files in my external HD, some of the file and folder names are coloured green... and it's those files that I cannot open or move.
When I right click on the files or folders and go to properties > advanced -- I can see the "encrypt contents to secure data" box is ticked and this is on all the files that I cannot open.

This is what I get when I untick the box and click apply;

Any idea how I decrypt those files? I am pretty sure Truecrypt didn't do it... and it isn't all my files... thankfully My Pictures and My Music seem OK.

 

[GSDog]

Thanks for that explanation. I had no idea about that and it means I have basically lost all my movies, emails, etc.

Oh well, **** happens and as you say there is nothing I can do now.
Thankfully all my pictures and family stuff were not encrypted, so at least I still have the most important files.

 

[GSDog]

The weird thing is that a lot of the files, such as emails, were all archived as .rar and I am pretty sure I didn't chose to encrypt them... so I don't understand why or how they were encrypted...

 

[GSDog]

I have another slight problem... I can't seem to delete the encrypted folders and some of the encrypted files...

I get this message;

Is it possible to delete them without formatting the drive?