DVI port+external monitor help

[halfxprice9]

I own a 2008 regular Macbook (OS X 10.5.8). My DVI port is busted, which I can live with, but the problem is that now my computer thinks that an external monitor is constantly plugged in. This becomes problematic when I open a program and the window will disappear to the "other" desktop. Also when I plug in a mouse sometimes my screen will shut down because it assumes I'm using another monitor. Is there anyway I can fix this problem, short of buying a new computer? Thanks