Hi Nadya,

>Yes, what is it: Any product or a product?
>In general, when an product installs, it should register itself with Internet Explorer. This allows the product to specify how Internet Explorer should handle files associated with it when referenced from a web page – for instance, it allows the product to specify whether the user should be presented with a warning dialogue before such a file is opened.

>I don't understand the first phrase, First of all, what if the system doesn't have Interner Explorer (as Dragan noted),

It's the same for all browsers.

>secondly, what does "an product" mean in this context: any product or a product or it is almost the same?

Every product that registers a file extension, so the files can be opened directly in Explorer or with ShellExecute, for example. See my message to Jim (Re: Flaw Could Enable Web Page to Launch Visual FoxPro 6.0 Thread #696759 Message #697036) regarding a little more explanation on this topic.

HTH,
Armin