Interrupts, limit switches, and IR board

[Neurovirus]

For easyC Pro,

how can u get it, so that when the limit switch is pressed and outputting a 1 to the microcontroller, to stop the motor?
Right now I have

Set PWM3 to 195

Get Interrupt

Set PWM3 to 127

which doesn't even make the motor move, at all....

Also, I would like to know how to use the IR board. I'm guessing you'll have to use the interrupt block, which i don't even know how to use.

In the end, I need someone to explain the following:

-limit switch, implementing it with easyC
-the whole Interrupt block, what it exactly does, how can i make it to control a PWM output
- IR board, tho I think if i know how the interrupt block works, I could figure this out on my own