HELP! Cant Delete Files From My NEW 4TB MyBook

About a week ago I bought a new 4TB MyBook drive. I spent several days transferring files from other drives. After the patrician I had 3.63tb of free space. Currently I have 1.72tb of free space.

Having transfered over a tb and deleting them from the drives they were on I am no longer able to delete files from my new drive! Last night my lap top crashed. I restarted it without any problem. I turned off the lap top when I went to bed and when I started it back up this morning I received the following Windows Msg:

In the past when I have run a scan on other external drives I have wound up losing a lot of files. Is there any way to restore the ability to delete files without risking losing files? Part of the TB+ I transfered are 2 large folders, Music and Photography, which are irreplaceable.

My lap top is running Windows 7

Mostly such issues are due to partition error and windows fixes this issue upto the extent. But I would suggest to take a backup of data before going to fix the drive to prevent data loss related issues.