I cant connect to net using long wire from router....but when using short there is a connection....

There are two possible problems. Bad wire or wrong wire.

A router to PC connection requires a straight through cable, since the short cable works we know that it is a straight through cable.

Take a close look at the writing on the wire see if it says what type it is (straight through, crossover, rollover, etc). If it doesn't say what type it is:

Take both of the wires and hold them next to each other with the prong facing up.

Look carefully and see if the 8 wires inside are in the same position for the long wire as they are for the short wire. If they are you know you have a bad wire. If they aren't your long wire is likely a crossover wire.

If this answers your question please help me out and leave feedback!

Thanks and good luck!