I don't mean to be an annoyance, but I think you missed my point a bit, I'm looking to use the laptop specifically for Busking (in the high street etc)....to allow me to play my electric guitar to the public or cash etc....
So i'm thinking of plugging into a laptop to achieve this...

I thought it would be portable, allow me to play electric guitar though it, and also not give me worries about power sources etc. (...I have a suped up computer at home for recording music)...