Amiga 500 won't boot - Can I boot from DF1?

[bill2reg]

I have an Amiga 500 that's been sitting in storage for years. I thought I'd hook it up to see what happens. I have the 512K ram option and an external floppy. It powered up OK as did the monitor but it won't boot. The bootscreen shows up, but when I insert the disk, nothing happens. I'm guessing DF0 is bad. Is there a way to boot from DF1 (external)?

[bill2reg]

I have never upgraded the ROM, so it must be 1.3. Is it difficult to remove the internal floppy and replace it? I have no idea what the components look like.

[bill2reg]

It is 1.3. I wanted to know if it's difficult to remove the internal drive and then take the external drive out of it's housing and install it as the internal drive.