Instructions. Sell your old computer parts on eBay. It may seem too obvious, but most online forums recommend placing your used computer parts on eBay first. You are more likely to get (close to) book value for your used parts on eBay than from anywhere else.Visit ComputerPartsAuction to sell your old computer parts.ave. You probably won't use your old computer very much after you purchase a brand new one. You may wish to use parts of the old computer, though, such as the hard drive. Instead of letting the rest of your computer sit and go to waste, consider selling off parts of the machine.