WMP10 not opening up when double clicking an avi..

[DualMonitors]

i purchased a new digital camera and made some avi files to test it. saved them to a file on my hard drive. when i double click an avi, Windows Media Player does NOT open up, yet, the sound of the avi starts, so obviously, something is "playing", but there is nothing on my monitor to show that, and there is not WMP interface displayed (no image of the avi is playing, ONLY the sound).

may i please ask how to resolve this?

FYI: i have a dell computer, something like 2.2GHz, an Nvidia video card with 1 dvi and 1 vga output, a samsung 21.3" LCD connected to the vga output, and a dell 24" (16:10) LCD connected to the dvi output.

i tried to re-download WMP 10 from Microsoft, which was successful, but the situation is almost the same: that is, the sound comes on, NO WMP interface visible (no controls), but on my secondary LCD (the 21.3" Samsung), the avi starts to play in FULL screen mode (no controls of any sort visible). the only way to "get out" of this is to click the WMP icon near my start button at the bottom of the screen, and when WMP opens up, THEN, the avi starts OVER again from the beginning! Of course at this point, i then have the various controls (start/stop/fast forward...etc) available to me.

i have no idea what's going on! any help would be most appreciated.

thank you in advance!

[DigeratiPrime]

download GSpot Codec Information Appliance. It will tell you what codec the file needs and whether or not you have an appropriate codec installed to play that media.