If you are sure that you have blown the fuse (ie there are no lights or display on the radio ), then you will have to check the fusebox and replace the fuse. Check the Haynes Workshop Manual if you have one. If not . then there are quite often labels/symbols on the fusebox lid showing which fuse feeds the radio , but if not, then visibly inspect all the fuses until you find one tha`s blown. If it`s not a standard radio fitted, then it might also have an "in-line" fuse which can be found in the wiring at the back of the radio after it has been taken out from the dashboard.
RegWorts, May 2008