My dell inspiron 15 3000 series keyboard isnt working & im havn 2 use tha mouse only

Try this...

1. Uninstall the keyboard driver.
2. Reboot the computer (without reinstalling the driver).
3. When it restarts, it should reinstall the driver on its own.

If this doesn't work, you may wish to try connecting an external keyboard and see if it works fine. If it does, then it could be the keys themselves that are the issue.

You may also want to try updating the Synaptics Driver if the above doesn't help.