Install the battery but the flashlight doesn't work. what's the problem, below is my

Install the battery but the flashlight doesn't work. what's the problem, below are my solutions.
1. please check if you installed battery with its incorrect poles touch? (Battery negative pole towards the tail cap)
2. Please let flashlight body connected in correct way.
3. Please make sure to let the tactical ring on body tail is in its right location ( ensure no any leak or not loosen)
4. Everything is OK and the battery is also installed well, please make full press click the tail button to turn on the flashlight. (some flashlight Tail button is for turn on/off and for momentary on by half press while the side button is for mode selections)
hope it is a useful information.

This should get you enough information to make short work of resolving your issue. http://www.candlepowerforums.com/vb/showthread.php?338889-BASIC-FLASHLIGHT-TROUBLESHOOTING-GUIDE

I think they are suggestions for others having trouble, not a request for help. That's how it reads to me anyways.

nbp,
I agree, it was written as an instructional, but the linked troubleshooting guide is more complete and more easily understood.

If m4a1usr hadn't already done so, I would have posted that link.

If it is new simply return as not fit for purpose and have a refund or a replacement.

The OP left out one critical step:
When all fails, swiftly and repeatedly strike it against a hard unforgiving surface until it works or until you amass mental satisfaction!

I've had lights that didn't work that I unscrewed the sections a few turns and then tightened them back up again either they were a little loose or debris got in there. sometimes you can twist the battery around in the tube and if there is oxidation the twisting action can scrape through it to make contact.

What type of light is this? The Olight S1 takes the battery with the + terminal towards the tail instead of towards the head. Also, are you able to see the contact points at both ends? Some makers will include a small plastic shim to keep a battery from making contact if the battery is shipped with the light and it must be removed to make it work. When you follow the trouble shooting guide and bypass the tail switch with a paper clip does the light work? Just a couple of thoughts...