1998 ford f150 just stopped working while driving

Go to the solenoid on the fenderwell .Look where the positive battery cable goes to the solenoid,there should be a group of wires attached with the battery cable,one,or two of these all fusible links,one maybe burned into.Pull on them,if one of them is burned into,it will pull apart like taffy.If so replace it with fusible link wire,from the parts store.Also,check for blown fuses under the hood in the fuse box.If there is a blown fuse,or burned fusible link,something caused it,so you will have to figure out the reason.If all this checks out,and you find nothing wrong in these areas,check the ignition switch.It may be bad.