Turn off red, wavy underlines for spelling errors

   1.   Click the Microsoft Office Button , and then click PowerPoint Options:

   2.   On the Proofing tab, click the Hide Spelling Errors check box:

   3.   Click OK.

This just turns the underlines off; it doesn't prevent PowerPoint from checking spelling as you type.

To stop check spelling at all, just click Check Spelling as You Type check box:

Turning off Check Spelling as You Type relieves PowerPoint of a small processing burden, making it run a bit faster.