This has been going on for some time but now it's just getting ridiculous.

Applications such as AIM, Xfire, and mIRC can't go more than three minutes of disuse without disconnecting randomly. And as for Xfire, it'll even disconnect while I'm using it. Strange thing is, I don't think this problem occurs with other computers on my LAN (they're not mine and I use them sparingly so I'm not completely sure).

I assume this has to do with my router, but I don't know what setting to alter.

This is my router, by the way: BEFSX41