Hello,
Just bought a 2003 lt 80 for my daughter. When we picked it up, the bike wouldnt start. The guy replaced the fuse and it started right up. My daughter rode it around and everything was great. The guy had mentioned that the battery goes dead after a few days if its not started... So we got the bike home, and now it wont start. The fuse is blown. As soon as we replace the fuse, it blows... Even with the ignition off, it blows. Please help

 

Welcome to the forums.
Obviously a dead short somewhere.
I'd start by checking all the wires and see if there is a wire wore and grounding.
I'm not great at electric problems.

 

With many quads a common cause of blowing the main fuse with the ignition off is the voltage regulator. Disconnect it and see if you can put a fuse in without it blowing. If you can, plug it back in and see if the fuse blows. If it isn't that, it is a wire shorting to earth between the fuse box and regulator or ignition switch.