Internal Hard Disk becomes HOT!!!

I've got a internal hard disk and as you use it for more few minutes it becomes hot and the longer you use your laptop it gets hotter and hotter. Well it started when I used a external hard disk, when I'm about to transfer files in my laptop to the external hard drive my laptop hangs up and then i waited for about 30 minutes but it still doesnt recover and then when Ive decided to remove the battery to force it to shut down I realized that my laptop is hot. And I discovered that it is the internal hard disk that becomes so hot. So I've removed the hard disk inside and waited for it to cool. And then I put it again in the laptop and turn it on and it says ... AUTOMATIC REPAIR.... What does it mean???? I waited for 2 hours and half for it to finished but it only reaches up to 40%. The Hard disk is so hot so Ive gotta remove it again....
Please help me...
What happened to my Internal Hard Disk ?
can it still be used?