Worksheet rows stop at row 298

[SRMPURCHASE]

I cannot seem to open any rows below 289, when I try to insert a row I get the "cannot push non-empty cells off the end of the worksheet" error. Somehow I set the very last row in this worksheet at 298 and no more. Help Please?

 

[DanteAmor]

is always at 15, someone mistakenly selected the rows and reduced them to 0

 

[RoryA]

If you set a really small row height, but not quite 0, then the Unhide command doesn't work to show them.