MOV is the prefix. Their likely extension .MOD (they’re MPEG-2 files).
Any MPEG-2 decoder should work. (The software bundled with the camera should have included one.)
Standalone Players
Media Player Classic:
http://sourceforge.net/projects/guliverkli/ very compact and tidy - just extract to your desktop, then drag-and-drop your MOD file onto it for playback.
VLC Media Player:
http://www.videolan.org/ An all-in-one player with lots of bundled codecs, including MPEG-2.
Filters
Filters will make playback within Windows Media Player possible.
GPL MPEG-1/2 DirectShow Decoder Filter:
http://sourceforge.net/projects/gplmpgdec
ffdshow-tryouts:
http://sourceforge.net/projects/ffdshow-tryout Bundles a lot of codecs, including MPEG-2
There’s also commercial MPEG-2 decoders sold out there, for example by Elecard or LEAD.
Commercial DVD Software
Any commercial DVD Player (WinDVD, PowerDVD, etc.) should also have an MPEG-2 filter that allows MPEG-2 playback in Windows Media Player. Note that Windows Vista Ultimate and Home Premium already have MPEG-2 and DVD playback capabilities bundled.
As for the MOI files they’re either thumbnails (viewable with any image viewer - try renaming to JPG to see if it works) or files that contain metadata (perhaps a text viewer like notepad or wordpad can read them then - try renaming to .txt to see).