Agoraphobia Horror Film

by Betsy

There is a movie about a girl who is afraid to leave her apartment- she works from home and her friends come visit her. I don't remember much about it except a staple puller attacking her, a knife moving towards her on its own, and a scary face showing up next to her during a lightning storm while she huddles up by the kitchen counter.

Also, I believe there is a Halloween party at the end of it- something about a guy being a serial killer or killing one of her friends, and her other friends go into a barn and trying to find him, and she watches from cameras on her computer.

Anyone know what this movie is? I'm at a loss, but I remember it scaring the crap out of me.