Issue with highlighting a cell block

[lilwhiskers]

I am very new to Excel and this is probably a very silly question but some how I have turned off my cursor to highlight a cell block. So when I click on a block, it doesn't highlight the edges and when i select multiple cells, it won't highlight those either. Can anyone tell me how to turn it back on??

Thank you!!

KC

[JeffreyWeir]

Does this happen in just one sheet, or every sheet in a workbook, or in every workbook you open?