|I'm just going to take some wild guesses. Maybe they will uncover something & maybe they won't.|
It sounds like something or someone is "deauthenticating" the connections. It could be someone, on the block, playing with backtrack. If that's the case, maybe you can disable the SSID broadcast on the router. I would also check the router logs, to see if PCs that don't belong to you, connected. Most people don't bother to erase the logs if they connect to someone's router.
I would enable MAC filtering no matter what the logs say. Add the MAC from the latptop so only you can connect.
Let us know what you find.
How do you know when a politician is lying? His mouth is moving.