Hey Nego

It could be that the new radio you have is defective and caused the fuse for
the radio to blow:
A fuse is like a circuit breaker in your house that causes current to stop
flowing when a line is drawing too much current. Unlike allowing itself to
be reset, a fuse permanently opens up and needs to be replaced - when that
happens it is referred to as 'blowing'.

Check your fuse box. It is located most likely under a little trap door next
to the driver's side left knee. One is most likely labeled "Audio" or
"Radio". In the fuse box you'll find a special little tool that looks like a
chubby set of tweezers  -- use that to pull the fuse out.
Once out, you'll see a loop of wire through the plastic on a healthy fuse.
Your fuse most likely doesn't have that little loop and needs to be
replaced.
It is most likely a 10Amp fuse. If you have spares present in your fuse box
(they are labeled), use them but make sure they are of the same value.
Don't use larger values as that can do damage!

Automotive supply stores sell an inexpensive and easy to use tool that
allows you to find voltage on wire. It has lights indicating voltage level
and a wire on one end that you attach to the chassis of the car. The tool
has a needle-like probe that allows you to poke through the insulation of
wire to see if they are alive or not. See if you detect 12V on the power
wires to your radio (the instructions of your radio will tell you what wire
should be connected to power). From there, you should be able to see if you
did your work correctly. If no problems are found, you may want to bring it
back and try it again with a replacement radio.

Sorry if I went through tedious details, but just want to make sure you
understood what I meant. Not sure what your level of expertise is.

Hope this helps
Remco