I have an old computer that cannot turned on. I sent it to the repair shop, they told me that my hard drive got toast. What i did not later is that my computer was fine , only that my monitor is having problems when i tested it on another machine.

So either my repair ppl are lying to me or that they have spoilt a good CPU.

So is there any indication to know whether a hard drive is burned? will turning a burned hard drive will cause some short circuit to my home?

After slowly drudging through your extremely poor grammer and spelling, I'm going to assume that you are asking "How can I tell if my hard drive is toasted?" Well, if you try it in another machine and it works then its not the HDD that's the problem, it's somthing else. If the drive doesn't work on another machine, then it might very well be the HDD. And no, using a fried HDD in a computer will not short out anything in your home.

--Chris

What has your CPU got to do with the problem. yeah when connected to another pc you can run diagnostic software on the drive to see if its broken and if the problem is fixable