Hi AGCGirl,
Probably you have a paragraph rule on.
Open InDesign, don't open a document and choose your text tool.
Now the options for Charachter and Paragraph are visisble. Choose the charachter options. At the right hand side you see a little black triangle, click on it and you will find a list of options and one of them is paragraph rules.
In this menu at the top you have 'Rule Above' and probably it will be activated, just deactivate it.
Then quit InDesign and restart and you problem will be gone.
This workflow is when it happens in every document. If it only happens in one document, then you open that document and with nothing selected you do the same as above without the quitting of InDesign.
It should work
carlow