Microsoft Excel Error: Range Specified

Greetings, everyone!
I'm not very familiar with MS Excel, as I use MS Word more. This week however I have a project I have to complete in spreadsheet. I got this error and the Help assistant keeps giving me the wrong answers and entries. Can anyone help me with this problem? Thank you all so very much.

Microsoft Excel
The command could not be completed by using the range specified. Select a single cell within the range and try the command again.
OK
