Dell Vostro 3500

hello all i am jack from florida I own a dell vostro 3500 running windows 10 21h1 it has a intel i5 m480 2.66ghz and a 500 gig hdd with 4 gigs of ram. i have a lot of lag and sluggish behavior as i have lot of work i need it to be fast/light (it sometimes overheats) any help is appreciated !