If you pulled things apart to clean....maybe something didn't get plugged back in correctly or at all. You may have to go back to pulling things apart to verify you have everything plugged in correctly.
Last laptop I pulled apart, to access the MB and replace the fan, the ribbon cable on the keyboard had to be disconnected. When I put it all back together I didn't realize the cable was slightly misaligned. After powering the laptop on and testing it out, 1/4 of the keys didn't work or returned different keypresses.....I had to take everything apart again to access the keyboard ribbon cable and fix the issue.