I thought I'd try this as I had a battery which lasted about 2 mins before starting to beep and then another few mins before switching to standby.
I was going to try and construct a replacement using NiMH AA batteries but gave this one last shot. I just took it out the plastic casing, wrapped it in cellophane and stuck it in the freezer for what was 36 hours. Took it out to warm up and dried off any condensation (note, leave on wrapping till back at room temp).
Then put the battery in and only had a chance to use it briefly , but it went from 50% down to 40% in about 15 mins (and that was installing a program so using the HDD etc) , so its looking like its back to a useable state! I need to do a couple of full charges and discharges, and then may stick it in the freezer one more time if I think its required, but touch wood, I should be able to get a couple of hours battery life out of it.
So this, fairly astonishingly, does work!