You can't change the description of an item , including the title, if you have bidders.
You can cancel the bids you already have (losing them forever probably) cancel the auction and relist.
Unless your title is a total misdescription of the item, let it ride. I assume you were willing to sell the computer for $30 or you would not have started it at that price.
Remember you don't know what the maximum bid is of your high bidder. Also be aware that most bids arrive in the last few minutes of a listing. For example, you may have a bidder using a sniping service whose bid will not turn up until the last second of your auction.
