First I would suggest using online etiquette and use capital letters when needed..ie not all the time.
Second I would suggest stating what problem you are having.
The AB SLC500 manual is here>
http://www.ab.com/manuals/cp/1747-um011c-en-p.pdf
The software is RSLogix500>
http://www.software.rockwell.com/rslogix/
If the SLC500 is connected to a machine AND you have the drawings for that machine there are some steps you can take to determine if an input or output is not functioning correctly. It would be even better if you have a copy of the program but sometimes its not needed.
On the plc input and output cards will be led's that light up when an input or output is active...they should if working.
Test your inputs individually to see if the led's light, at the same time record which input is connected to which input device. This you do if no drawing or printed program copy is available.
Test your output devices manually..ie disconnect from the output card and connect manually to test the device. I usually use a N.O. pushbutton connected to power source.
This will tell you whether its a failed input, input device or output device. That eliminates alot.
If you read the manual you will also see there is a section to show you what faults have occured by using the LED's on the processor (not the input/output led's).