Ok. that leaves the fun part.. getting the tip off the tube. There are two types of tubes from the DX lasers. One has "laser pointer" stamped into the pocket-clip, and an aluminum-looking button. This tube is thicker, and actually easier to open.
The other tube had a plain chrome clip, no writing, and a chrome-looking button.. This one is a real party(sarcasm intended) to open.
For the first type, clamp the "tube" tight about 15mm down from the tip(leather comes in handy to prevent damage), then clamp the tip carefully with vise-grips(again leather helps you not to destroy it) so you don't crush it, again tight right at the end, and wiggle/pull until it comes out. The module will easily push out the tip-end, once unclamped. DON'T try to push it out past the button end.
For the second type, Clamp the tube in the same spot, very firmly to prevent the module twisting inside(death to the driver). Clamp the tip in the same manner, and unthread it. Unlike the first type, this tip is threaded onto the brass module inside. To reassemble this one, you have to thread it back together the same way. First insert the module so the button lines up, clamp the tube again to hold it, then thread the tip back in. SOMETIMES you can thread the tip on the module first, then line up and press the whole thing back in.
On either one, the tip is press-fit and VERY hard to remove.
Replacing the switch is a cinch, provided you have soldering skills.
Good luck, and let us know how it goes