250mw green laser is broken please help

i am not a expert with lasers but i found my 250mw green laser and i don't know what it is called but the top of the laser came off, it came off before and i aligned it and not it came off again and it wont align, please help!

i cant upload pics so the part that fell off is a circle with the green diode in it. the part it fell off puts off IR laser but i would love to figure out how to put it back on

Well, pics would help, a lot...

This way it is uncertain what are you talking about, and what's the problem.

And about which green diode are you talking? There is just an infrared diode in green lasers (except for direct green diodes, but those are expensive).