MyBook Essentials 1TB permissions issues

I got this drive for christmas (09) and I worked fine for the first day.  However now I am having SERIOUSLY AGGRAVATING issues.  I get messages telling me I do not have permission to write anything to or modify anything on the drive.  I have backed up some stuff and there is a bit of media on there but now the 800gigs of spare space is totally useless.  It’d be swell if someone could tell me why my hard drive is telling me that the ADMINISTRATOR of my computer (me, the only user) doesn’t have the permissions to write or modify files, and why it wont let me change said permissions. 

I have similar isasues. I ca n not log on to any shared folder using the names I set up with full access rights. The only way I can access shared folders is to set the everyone user to full access. THAT is a theft waiting to happen.  Can anyone assist in shedding light on this?  I have had it for closae to a year and never have been able to use it.

MyBook (blue ring) , 1 tb, firmqware updated 1-1-10