dashboard is not useable

Please help – two weeks ago I was unable to log in or use my blog. Now I can but half the admin options are gone. I cannot add plug-ins, check my counterize file (says I don’t have the authority to) and the blog has been squirrly ever since it was “fixed”. I am not that computer literate to be able to go behind the scenes, check this file and that, I just know that before this “meltdown” it was easier. Now, it is very, very frustrating.