No-one would sell you a Warranty on a five year old laptop unless it wasn't worth the paper it was printed on. Put a small amount of money aside monthly in case anything goes wrong. That way you'll have the cash to any for repairs if necessary.
The part most likely to fail is the hard drive so make sure you backup externally and regularly. That part is one that you can swap out and install Windows on a new one. Make a clone on to a new 2½" hard drive or Solid State Drive.now and every six months and you'll save yourself a ot of work and trouble. EaseUS Disk Copy is a good utility to do that job.