Always check how you threaded the machine first when you have a problem like the one you described. Did you pull up the thread guide bar? Look at the picture. The part I forget is the bar on the back of the machine.
I usually put a postit note to tell me which needle plate is in place. I have ADD and age, too.

You might try putting alcohol on some heavy thread and running it throught the tension to clean it.
Dust can be a big problem and the machine surely makes a lot of it.

There are mini attachments for vacuum cleaners that are not very expensive. With one of those you can vacuum instead of blowing the machine with canned air.