My Dell latitude d830 laptop suddenly started acting like all typed keys are preceded by the left control key. In all programs.

It is not a hardware problem because my USb plug in keyboard does the same thing. I also made sure that all the sticky key and filter key settings are not clicked in the accessibility settings on the control panel.

and I updated the Dell latitude bios from the Dell support website.

It still is a sticky left control key??

What is up? Any ideas?

I also ran two anti-virus packages too, seems clean

Also this has Windows XP on it, with the latest updates fully installed

Had this same problem on an older Dell Latitude I own. The problem absolutely is the keyboard. To test and verify, unplug the built in keyboard, boot it with just a USB keyboard plugged in, and it will work fine (what has happened is that the built in keyboard has an issue with a "sticky key", and this is going to consistently send that key stroke signal to the OS, no matter how many external keyboards you have plugged into it). Ultimately, replacing the keyboard is the only way to resolve the problem.