The keyboard on my Northgate netbook is funky. Sometimes it jumps to an earlier line without any warning. Any ideas as to why this should be happening?

Sometimes that can be caused by something stuck on the key, or if you've spilled anything on the keyboard and the keys are sticky. Try removing the key with a butter knife (careful not to break the hinge) and checking it out. It also might be worth picking up some compressed air and blowing out the keyboard, it might fix your problem and it's a good thing to do every month or so.

Other than the keys being stuck, I would think either some kind of driver issue or a virus. If you have an antivirus, update it then run as full and complete of a scan as you can, and just let it run overnight. If that doesn't solve the issue, try looking on the manufacturer's website for a driver update.

Just out of curiosity, what program are you using it with? It might be related to that program as well.

As a last thought, it could be a problem with your mouse. Try cleaning off the touchpad really well with alcohol wipes (after turning the computer off). If you can disable/enable the touchpad with a button or something, you can try that as well (or plug in a USB mouse and disable the touchpad to rule that out as a possible problem).

You got a problem in the the microchip of the keyboard which is responsible of getting the user input.
Get the keyboard repaired or get a new.