Reinstall/Reboot problems

I am using a G4 under OS 9.1. I have been using DP 2.72 and Allegro 2002. I use the Allegro to print off scores, after having saved the DP files as generic MIDI files which I then import into Allegro for editing and printing. Now the Allegro won’t save the files after editing ? I just click on ‘Save’ or ‘Save As’, but no file save dialog box appears ? I have re-installed the Allegro twice, but it makes no difference. I have also tried rebuilding the desktop, holding down alt-squiggle (having been told that the alt key is equivalent to the option key) but the rebuild dialog box does not appear as it has before ?

So I decided I would re-install everything. I have tried to re-install OS 9, but it just won’t let me. I have a copy of OS 9 for Dummies which tells me to re-start holding down the C key, but to no effect; it just starts with the usual opening chord, opens up the tray with the system disk in it, there is a small flashing file icon with a question mark on it, and then it starts as normal ?