Use a GParted LiveCD/USB
. I've used it to reformat and resize partitions, and it works like a charm. You can move your partitions around, resize them, delete them, reformat them, etc. Basically any way you want to handle this situation can be done with it. I'd recommend backing up your data, then using GParted to delete your partitions and start over by re-creating them. Or you could just use it to resize your current partitions if you're nervous about complete OS reinstalls.