Is it all right to use powerpoint images on your website? For example, If I draw an arrow using the shapes tool, can I then cut the image from the powerpoint and save it, Then use it on my website?
Yes, you may. I contacted Microsoft support and they confirmed this. However, I don't know how much trust I would put into a chat representative for legal concerns. So, I've provided some more information...
Here is an excerpt from Microsoft's own website:
Clip Art and Sample Art
The End-User License Terms that accompany your software describe the permitted commercial uses of images, clip art, animations, sounds, music, shapes, video clips, and templates that accompanied the product. Find End-User License Terms for Microsoft products.
The Clip Art and Media gallery provides a compilation of artwork. See the use terms for the description of permitted uses. If those terms do not meet your needs, our Clip Art partners at Office Online provide a variety of images you can license directly.
In the absence of language to the contrary in the License Agreement, Sample Art (which includes images customarily found in the "sample" folders within Microsoft operating systems) may be used for personal use only. You may not sell, lease, or distribute Sample Art, or any materials you create that use Sample images, for any commercial purposes.
Additionally, here is an excerpt straight from PowerPoint 2007 EULA:
Media Elements and Templates. You may copy and use images, clip art, animations, sounds, music, shapes, video clips and templates provided with the software and identified for such use in documents and projects that you create. You may distribute those documents and projects noncommercially. If you wish to use these media elements or templates for any other purpose, go to www.microsoft.com/permission to learn whether that use is allowed.
You may find out additional details here. For any further inquires I was suggested to contact microsoft directly, in writing, at:
One Microsoft Way
Redmond, WA 98052-6399
To expand upon Johannes' answer, a simple arrow like you describe in your question is not likely to pass the threshold of originality.
The details vary between jurisdictions, but for example, the Compendium of U.S. Copyright Office Practices states, in section 503.02(a), "Minimal standards: pictorial or graphic material":
"Similarly, it is not possible to copyright common geometric r. figures or shapes such as the hexagon or the ellipse, a standard symbol such as an arrow or a five-pointed star."
Thus, you can safely use your arrow without having to worry about copyright issues. Of course, if it was a really fancy arrow, with a substantially original design, the situation might be different.