Fill data automatically in worksheet cells does not work anymore

Dear all,

thank you for reading. I have a problem with my excel program and was not found a solution with google: Filling data automatically in worksheet cells does not work anymore.

I reboot my system (win 7, 64-bit), then start excel (MS Office Prof. Plus 2013) with an empty worksheet (no filters, etc.). Then I am typing 1,2,3,4 into cells A1 to A4 and select those 4 cells. Normaly, when I move my mouse pointer down to the right edge of selected cells, the pointer changes to a 'plus' sign. But this does not happen anymore and therefore it is not possible to click the edge and expand the selected cells and filling data automatically (1,2,3,4,5,6,7,8,9,...)

On the other hand, I can not move the selected cells, by draging the edge of the selected cells to an other position.

Does anyone have similar problems? How can I repair this?

Regards,

Hans.