I got 3000mah ni-mh battery pack last week. When I plugged it into a tank it had absolutely no charge in it. So I charged it for about 6.5 hours with a standard HL charger. Last night I plugged it in my PIII and I got a total of about 5 minutes running time... So, do you think its dead?

Probably, try shocking it back to life before discarding or taking it apart for parts.

leggeron, swathdiver is right.. try hitting it with high current ... Hook it up to a car battery charger on 2-6 amps 12volts..I have used up to 10 amp charging but only for 20-30 second intervals. Stay right next to the battery and as SOON as it starts to get warm take it off.. Keep an eye on the plugs too, they might get warm with the charging..

I've done this many times to revive batteries, it does work just don't leave it on and walk away.. You have to stay near it to monitor the temps.
Let it sit for a couple mins after it's done until it cools down then run it.. Don't run it right down to nothing.. After you've run it, let it cool down completely then charge again..

Will try, thanks