And another thing:
How come, when I start the IDE, it sometimes comes up with the last sketch I used, and sometimes comes up with a useless new blank sketch, which I then have to delete.
Why does it do this ?
If it is supposed to be saving the name of the last sketch I used, in some config file or registry entry somewhere, why doesn't this happen every time ? It would not surprise me if this bogus behaviour is somehow linked to the COM port conflict.