I install a new internal drive (WDC WD 2500 AAjB-00j3A0 ATA ) into my G4 (mirror doors-1 GHz PPc-2GBs Ram w/OS 10.4.11 ).All went well I thought exceptwhen I tried to start up from that drive , I got the " not allowed symbol " - circle W/ line though it -why can't i boot up from the new drive...