But what I observe is that when i have only the right side speakers hooked up its fine but when i hook up the left side speakers (comp) thats when the fuse go out. what gives?
It's more than likely that one of the speaker wires got frayed and was shorting out on the chassis... by moving the speaker wires around when you reversed polarity.. you might have just moved the wires enough to prevent the wires from making any further contact with the chassis.. thus eliminating the short..
I'd still check the wires again for signs of wear or else you'll have an ongoing problem.