I saw a place selling Celeron 500 machines the other day for $70 on sale, regular price $100. They had blank hard drives. Yours might be worth $75. Just a rough estimate. Really depends on what someone is willing to pay on a machine that old.
"I would like to know what it's worth before i sell it"
Ooops. Didn't read the whole thing. You'd be lucky to get $75. I've got a similar machine that's being shipped to mom to replace the 4th one she's destroyed..