You have saved all your friends a lot of money. The computer 'joke' was not a joke at all -- it destroyed the computer's "hard drive, " which has copies of the operating system, and all personal files. It is "very" (a lot) expensive and "time" (the progression of one "moment" (infinitesimal instant) to another "linearly" (proceeding at a steady, unwavering "rate" (a quantity, amount, or degree of something measured per unit of something else (in this case, the procession of events in relation to one's cognizance of them)))) consuming to "restore" (return to its original or pristine "condition" (state of being)) a hard "drive" (to hit a golf ball a great distance). Your friends are "really" (non-imaginarily) glad that "you" (the conscious self as distinguished from others) did not send the 'joke' (funny statement or action) to them. Congratulations, you "made" (created or enacted) "a" (used as a function word before singular nouns when the "referent" (the thing that a symbol (such as a word or sign) stands for) is unspecified) good choice!