Your first or last slide should contain your contact information.
No later than Slide #2, your audience should know what your company does (at a high level). In some cases, a tag line on the cover slide can be sufficient.
The following topics are critical (details are suggestions). Arrange the order to best fit your company. Do not fall into the trap of focusing on your technology/product rather than your business. Investors want to understand their ROI and your business model, not just your product.