Presuming it's a TRX300ex, check to see if you have 12 volts on the black wire with the white stripe at the CDI box - if no, you have a bad handlebar kill switch or a broken connection between the black wire going to the kill switch and the black/white wire going to the CDI box - if yes, check to see if you have continuity between the green/white and yellow/white wires at the CDI box - if no, you have a bad connection or a bad pulse generator - if yes, check to see if you have continuity on the green/white wire to ground (check between the wire and the engine, frame and negative side of the battery - continuity is needed all 3 ways) - if continuity is good, unplug the black/yellow wire at the coil, check continuity between the terminal on the coil and the frame - if none, replace the coil - if good, check between the inside of the spark plug cap and the frame, if none, remove the spark plug cap and check between the plug wire and the frame - if good replace the spark plug cap, if none replace the coil - if all tests good, you have a 50/50 chance the CDI box or the pulse generator is bad. The pulse generator is the cheapest (about $35), but you have to remove the LH engine cover to replace it. That means a new gasket, new oil and about an hour or more to do the job. The CDI box is about $175 but only takes about 1/2 hour or less to change out.
There are other possibilities, but what I have described are the most common problems. The fact that you rolled it might mean the handlebar switch was damaged. If it's not a 300EX, then what I described only partially applies and/or the wire colors might be wrong. A TRX200DA and TRX300A are completely different.