what will happen if after crimping your cat5e cable with rj45 the reading from pin 1 to pin 7 is correct by using your Lan cable tester but connection between pin 8 is showing no connection, the connection is straight through, can the cable be used? Please help me

It should still work and give you up to 100 Mbps but without all 8, you can't get 1000 Mbps. See the following page on network cable pinouts and color coding standards for more info. If it were me, I'd just redo the bad end...........

You will end up using a bad cable that later you will pull your hair out trying to figure out what is going on. Either fix it or throw it away. "Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, Make an autorun.inf folder on all usb drives.