Old computer issues

Hi! I have an old computer that seemed to have lost it's windows program and we don't have the disk *grrrr*. I got it up and running again but turned it off when securing our wireless internet. It won't reboot now and tells me that the PRI (something) S.M.A.R.T. is bad. Any ideas? I would be willing to pay for the long distance call if you d-mail a number and know how we can fix it!! The computer is for the kids...I have a daycare and we play educational stuff on it. I had it on the internet prior to securing the wireless so we could go onto Starfall which helps immensely with the 4 y/o that has a speech impediment!! I just want to get it back up and running if we can! Thanks!!!