There are different ways to embed audio or video data so that the presentation automatically starts when a user enters the page. Similar effects than be achieved by using so-called animated GIF images. Avoid such constructs. Also avoid blinking text (implemented using the <blink> element) and automatically scrolling text (usually implemented using the <marquee> element).
It is usually easy to see whether a page contains auto-starting content. You just visit the page using a normal graphic browser on a computer with sound presentation capabilities. If you hear something or if you see any moving content, even though you haven’t done anything on the page, you have a problem.
If the page uses the (nonstandard) HTML element <embed> for embedding something that auto-starts, then a quick fix could consist of the removal of an autostart attribute from the element. However, you need to consider the element as a whole: if it has been designed to auto-start, it may lack normal audio or video controls for starting it!
If the presentation is not relevant to the purpose of the page, just omit it. For example, an animated image of a mailbox with a hand reaching out from it is sometimes used as a link to the author’s E-mail address. Replace it by a static image, or, better still, by text like “E-mail” or simply your E-mail address.
If the presentation is relevant and useful, such as an animation that illustrates how a system works, it is often best to link to it instead of embedding. At the HTML level, this typically means replacing an <embed> or <object> element by an <a> element. You can use a link that consists of both a descriptive text and a static image that suggests the nature of the linked resource. In markup, this could mean something like the following (to complement a textual description, not as a replacement for it):
<div>There is a short (5 min) video presentation that illustrates the installation process:<br> <a href=”instructions.avi”>instruction video<br> <img src=”video.jpg” alt=”” border=”0”></a></div>