You don't say what version of powerpoint you're using but, with my version (2003) I can use action buttons, selected via Autoshapes, to create hyperlinks to other slides within the document.
For example, slide 1 has the simple Q of 'What is 1+1?'. Under this I can set 3 action buttons, each with an answer of, say, 2, 4, & 8. Each action button has a hyperlink attached to it to direct what the next slide should be, either correct answer or incorrect answer.
If you have an e-mail add that can accept a ppt file (about 50k size) I have created a very basic ppt show to demonstrate the above. PM me rather than leave any private e-mail on this page.