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Maybe Wind Chill?
http://en.wikipedia.org/wiki/Wind_Chill_%28film%29

Just a guess, but maybe The Dollhouse (2002). http://www.imdb.com/title/tt2361487/reference
IMDB doesn't have any info, but it was asked and answered at this link which has some details. ...

If you're still looking for this movie, it might be Infested (2002) although the synopsis says flies.
http://www.imdb.com/title/tt0287497/reference

Darkness?
http://en.wikipedia.org/wiki/Darkness_%282002_film%29

Captivity?
http://en.wikipedia.org/wiki/Captivity_%28film%29