Click the Office button, and then click PowerPoint Options.
Click Proofing. Select or clear the Microsoft Office spelling options:
Ignore words in UPPERCASE.
Ignore words that contain numbers.
Ignore Internet and file addresses.
Flag repeated words.
Enforce accented uppercase in French.
Suggest from main dictionary only.
Select or clear the PowerPoint spelling options:
Check spelling as you type.
Use contextual spelling.
Hide spelling errors.