How do I open a downloaded program?

Get information on the full file name including extension. Almost all Mac software comes in a .dmg file. When you double click on that it open the Installer application which mounts the image on your desktop (it looks like another hard drive has been added).

Some application may arrive zipped, with a .zip at the end. These should open automatically with a utility already on your computer.

Two main scenarios:

1) You are missing the applications necessary to open these files. We can tell you how to replace them if this turns out to be the case.

2) You are downloading applications that aren't intended to be run on a Mac. Usually these have .exe at the end, but could be others. A lot of people download Windows software unintentionally.

This is where knowing what file types you have would be helpful.

.msi2 is usually associated with a Windows file type.
The usefulness of that in a Mac OS X system is nil;
but if you had a virtual Windows system running and
were expecting to use such a file in there, the other
OS would probably have to be up & running to open it.

The Miracle Traffic Bot software (I just did some searching)
is a rather odd duck, and perhaps it is not supported in the
OS version you have. I found nothing in a quick search to
indicate it would work directly in Mac OS X.

Miracle Traffic Bot - redirects internet traffic to certain sites:
http://www.miracletrafficbot.com/?hop=wesal

Contact: support@miracletrafficbot.com

The ".msi" filename suffix generally refers to files built for
the Microsoft Windows Installer. While there may be other
applications of the file type, they usually aren't used for Mac.

Anyway, it sounds like the software you are trying to open
won't work native in Mac OS X 10.4 Tiger, so it can't use it.

There are some open source apps written for multiple platforms
and of those, some versions destined for operating systems
other than Mac OS X (available from the same site page) may
have file types in them for Linux, Windows and others. Perhaps
you mistakenly got some file for a different OS, and not for Mac.

If you have Windows running in a BootCamp partition, then that
is where you would have to try opening up such a file; unless it
is some multiple platform application and you have the wrong
file for Mac, as suggested. You can try searching via Google to
see where the file type and systems involved may be at issue.

If that software runs under another application, perhaps it would
be able to open the file type. This is outside of my areas of interest.

Good luck & happy computing! 🙂

{PS: The site link above and the site have been reported to Mozilla
Firefox, due to the fact if you go there with Ffx 3.6.3 browser, the
site popups won't let you navigate away from their page. I had to
force-quit the browser to get out of their nexus!}