So let my start by saying that I'm 99% sure it's not a problem with the physical keyboard. As I type this now, it's working completely fine. It happens maybe 3 or 4 times a year, at complete random

Basically, when I turn my computer on and start to type, half the letters don't show up, unless I hit the key really hard, or 4 or 5 times in a row. Oh, and I'm on Dell laptop. So if I got to wikipedia and type in 'a song of ice and fire' I might get something like ' a sgo fca re'.

I've checked, double checked, and triple checked to see if any of my keys are stuck down, and they are fine. I'm typing this perfectly at the moment. I've even started in safemode with the mouse unplugged, and it persisted.

Restarting the computer doesn't fix it. The only trick that I learned is to turn the computer completely off and remove the power supply, then plug it back in and turn it on. Now this happens only like once ever 4 months on average, but it is annoying, though it usually seems to fix itself. I would just like to get to the bottom of this problem once and for all.

Oh, and googling didn't really help, since it was mostly about corrupt drivers, or rocks under the keys

 

It sounds like a very low level problem. Something is going wrong in a chip that doesn't go away until all power is drained from it.

Update your bios.

If that doesn't fix it, then I suspect that there is no fix.

 

If it's a problem with a chip, then you're probably right. But additionally to updating the bios, I would remove the keyboard and make sure that it's not a loose connection, or that there's dust in the connector (here's a tutorial).

You say that the problem only disappears if you completely remove the power? If that's the case, just to be sure, the next time it happens don't remove the battery and boot from a linux live-cd, just to be 100% certain that it's not windows or a driver.

You could also make a post in the dell support forum for laptops.