As to the miditxt files, I didn't even try to use them. Merely appearing in the Explorer window was enough to make everything freeze. And deleting them stopped it. So I can't use them again to hear music. I can't explain it.

The school computer definitely has hard disk trouble, with bad sectors, iffy folders and all, and it's a laptop, so we'll be returning it to base. Hopefully I'll be able to salvage more files first, and they won't be able to find exactly the same disk and have to replace it with a bigger one! That happened with our last one. It's just the time the whole business wastes when I could be reading the latest Terry Pratchett!

Penny