Error message

I have been working all afternoon developing a database and then
disaster hit. I accidently typed a "d" in a property field and didn't
realize it and closed the window. I am getting the following message.

"the Microsoft Jet database engine cannot find theinput table or query
'D' Mkae sure it exists and that its name is spelled correctly."

I can still open the database, but only in design view. My "Help"
feature isn't working now either. I can't believe I will have to start
all over. Any ideas from anyone?