2000 Accord clunks in the morning ?

Started as in what? Ignition, or shifting out of Park and taking off?

If the latter, and the car is an automatic, has the tranny fluid ever been changed? And if so, is the current fluid genuine Honda fluid?

you might need a tuneup and all around maintenance if it hasn't had much maintenance. like spark plugs, pcv valve, air filter, radiator flush, transmission fluid change, oil change.

none of the above will address a "clunk" so there's absolutely ZERO point spending money on routine maintenance when something is loose or broken.

yes. you need to describe the problem more completely. if you can't describe the problem, take it to an experienced honda technician who can sort it out for you.