IIRC the warrior doesn't have replaceable batteries, so might be worth throwing it out in the sun for a bit to see if that gives it a new lease of life. If not, i'd say its probably kaput.
Time for a new optrel eh?
i wish! looking today, they are a bit expensive for my pockets aha!
I started taking it home every other week and leaving it on the parcel shelf. not failed me since.