Please help - desktop issues

For some reason, my desktop has just started to "duplicate" folders! If I drag one of them to the trash, it takes both - they seem to be linked somehow. This is getting to be a real pain and I've looked everywhere in preferences to see if I've switched on a backup-type programme, but it's got me beat.

It doesn't do it all the time, either - just sometimes and I can't even home in on one specific type of folder - it appears to be just random.

I'm using G4 Quicksilver with OSX 10.3.7 - any help would be greatly appreciated

Many thanks

BOB