It sounds like your hard drive is dead. You are going to have to dig deep to get the computer going again.
reformat hard drive
Unfortunately, the full solution to this problem can be quite painful. We’ll start with some easier fixes.
System instability is often the result of what we call “software rot.” It can be the result of installing and uninstalling lots of programs – and the cure isn’t easy.
Reformatting a hard drive, by definition, erases everything. The big question is why did the technician NOT tell you that!
Erasing your hard drive before you give it away is important. Exactly how thorough an erase you need depends on your data and level of paranoia.
Occasionally, when moving a drive to another machine, it’ll show up as unformatted. I’ll look at some possible causes and actions to take.