Some keyboard keys not working on MBP

Since the recent 10.10.4 update, some keys on my built in keyboard do not function when pressed once but when pressed rapidly, they produce erratic strings of letters. Such as this one, compliments of the "U" key: IORTUYeqrtw. Other keys that don't work properly are P M J ; and 7. I used compressed air to clean under the keys but nothing changed. I also checked the keyboard settings and nothing is abnormal. I‘ve searched the forums and could only find issues relating to USB or bluetooth keyboards. The only way I was able to type this was to use Keyboard Viewer. Help me Obi-Wan, you're my only hope.

Someone -- not necessarily you -- has been eating and drinking over that keyboard, I'll wager.

No, that is not the case. Also, I don't believe that would explain several keys in different areas malfunctioning yet the adjacent ones still work fine.

Actually, yes it would. The way the keyboard is translated does not necessarily mean that you would lose an adjacent set of keys from a component failure. For example, all the keys in your example IORTUeqrtw are in the top row of letters, which sort of points to the sensor for the top row being erratic.

Is your battery swollen? It could be pressing on the bottom of the keyboard if it is.

You can also try an SMC reset (search for it) to see if that resets your keyboard.

Ok, that makes sense but I'm pretty sure that has not happened. Not sure if if the battery is swollen because it is the non-removable type (Mid 2009). Also, I tried resetting the SMC (Shift+Ctrl+Option+Power) the MagSafe light did not change but the battery charge indicator lights did turn on and then fade away. Anyway, that did not fix the problem. I also tried doing the NVRAM reset but was unsuccessful because the P key does not work.

Update: I was able to reset the NVRAM with a USB keyboard (on which all the keys work) but still no dice on the built-in keyboard. Also a note concerning the 'same row, IORTUeqrtw' factor: After the reset, the pressing the 'P' key was input as pressing the 'Mute/Unmute key. Not that it changes much but, just a note that they're not just malfunctioning within the same row. Does anyone know of anything else I can try before an expensive visit to a repair technician?

Your thread was moved here which is the appropriate forum for the subject. (Per your request.)