Loy Lum

Try using something smaller than your finger to press the open key (button). A smaller object may help to press the key all the way in. Also try pressing the key closer to the left end & closer to the right end, instead of the middle of the key.

Sounds like the connection between the blades & the motor is worn. Separate the driven blades part from the driving motor part. Look at both the driving & the driven parts of that connection for wear & breakage. If there are broken/missing/severely worn parts of either connection, replace them. You may have to get a whole new section with the motor or a whole new section with the blades, if not both. If they both need replacement, just get another Cuisinart.

Better leave the back pack where it cannot fall. Hindsight is so much better than foresight . I learned the hard way too!

Don't know about ruined screw head removal, but for future reference: Place the tool lightly on screw head & rotate axially 'til the tool drops into the screw head for a comfortable, firm fit, before applying pressure & torque for screw removal. If the tool does not drop in the screw head for the comfortable, snug fit, you may have the wrong tool or the wrong size. Try a different size 'til U get the right fit before applying pressure & torque to remove the screw. It can save you grief from a ruined screw head.