Ok, Alt codes generated by first activating your Number Lock on your keyboard then holding down the Alt key and typing numbers on the number pad (not the numbers across the top of your keyboard). If you do not have a separate number pad on the right hand side of your keyboard then your number pad would be the keys M,J,K,L,U,,O,7,8,9 (representing 0 to 9). You should see these keys marked with these numbers in blue.
Here is how to activate and type Alt codes:
Activate the number lock on your keyboard by pressing on Num Lk key, then while holding down the Alt key type 0176 (using the number key pad) and let go. This will insert the ° symbol.
Note: On some systems you need to hold down the Fn key together with the Alt key while entering the numbers.
Alternatively, if the above text is in a cell, let me know which cell and I will write you a formula that will automatically replace all instants of carriage return by another character say the dash.