Vista won't boot, I am afraid this is the hard drive.

First off let me say that any help would be greatly appreciated, I am at a total loss as to how to fix this problem.
I am not sure on the version of vista that my computer is running but I bought the computer when vista first came out so it would be a early version. My daughter messed with my electrical breaker box in my house and reset the electricity when I turned on my computer windows did not boot, instead a black page appeared saying that I would need to boot from a disc or dvd. I didn’t have a disc or dvd so I downloaded a boot disc(I don’t remember the name of the site that I got it from)
I then followed this tutorial that I found here http://www.bleepingcomputer.com/tutorials/repair-windows-with-windows-startup-repair/ which is about using startup repair. When I got to the place where it is supposed to list operating system instead of showing vista it shows nothing at all. I still went ahead and pushed next anyway and it said that startup repair can’t repair my computer. On the screen that pops up on whether or not to send information to Microsoft, there is an option to show problem details this is what it says:
Problem Event Name: StartupRepairV2
Problem signature 01: ExternalMedia
Problem signature 02: 6.0.6000.16386.0.0.0.0
Problem signature 03: 0
Problem signature 04: 65537
Problem signature 05: unknown
Problem signature 06: NoHardDrive
Problem signature 07: 0
Problem signature 08: 0
Problem signature 09: unknown
Problem signature 10: 1168
OS Version: 6.0.6000.2.0.0.256.1
Locale ID: 1033

Hopefully that info means something to someone because problem signature 06 kinda scares me.
Pushing on, I then clicked on “View diagnostic and repair details” This is what appeared:
Startup repair diagnosis and repair log
----------------------------------------------
Number of repair attempts:1

Session details
-----------------------------------------------
System Disk =
Windows directory =
AutoChk Run=0
Number of root causes = 1

Test Performed:
-------------------------------------------------
Name: Check for updates
Result: Completed successfully. Error code = 0x0
Time taken = 16 ms

Test Performed:
--------------------------------------------------------
Name: System disk test
Result: Completed successfully. Error code = 0x0
Time taken = 0 ms

Root cause found:
---------------------------------------------------------------------
A hard disk could not be found. If a hard disk is installed, it is not responding.

------------------------------------------------------------------
-----------------------------------------------------------------

So now for my main question, what does this mean? Is it my hard drive?
When I first started writing this post I though it was vista but now I am leaning towards a hard ware issue.

Thanks for any help that you can offer.

when you boot up, enter the BIOS to see if the hard drive shows up there. you do this by pressing a key (like del) during the boot process. check your manual (download from manufacturer if you don't have one) to see how to enter BIOS.
also download drive manufacturers diagnostic utility from their web site and boot from it to test the drive.

Thanks for your help.
I downloaded a free hard drive tester called hitachi drive fitness test and at first it said the hard drive was fine, I walked away from the computer for a minute and my 4 year old turned the computer off, when I turned it back on the software couldn't find the hard drive any longer. I didn't know the make or model of the drive so I took the computer apart and found that information and then I went to the western digital(the company that made the drive) website and downloaded a software to check that specific drive. It also can not find the drive.
Does anybody know of anything that would cause this other than the hard drive going out?
I looked into it and the hard drive itself isn't to bad to replace money wise but since I don't have a copy of vista I will have to buy a new operating system disc, which is a little bit out of my price range right now(being right before christmas and all). I would like to be sure that is what is wrong before I invest all that money, I would hate to find out something else is wrong after going through all that.

since you have things apart check connections to hard drive. there is a data cable and a power cable. unplug and plug back in. since there was a power jolt involved you could try a different power connector to see if it makes a difference. also if this is a serial (SATA) drive there may be a setting in BIOS to tell it to boot from the SATA drive.

Thank you for the suggestions, I went ahead and tried those and it still didnt work. I changed the hard drive ( I had an old computer with a 160 mb hard drive which is really bad downgrading from my 500 mb plus going from vista to xp) anyway I finally got the kinks worked out and the computer is working as far as I can tell. So it definitely was a hard drive problem and here I thought I had experienced my first vista problem. Thank you again for your help, I had no clue you could check a hard drive with software.

some western digital drives were warrantied for five years. goto WD site for warrant check.

I am having the exact same problem "When I got to the place where it is supposed to list operating system instead of showing vista it shows nothing at all." There is nothing listed. It says to "Load Drivers" but I have no idea where to go from there. I am given the option of Computer, System and Recent Places. Where do I go from this point? Any help would be appreciated.

Thanks,
Cash

have you also tried this "start up repair" . i am not very well versed in vista so you will have to explain exactly what happens when you boot from hard drive. and what happens when you boot from the dvd.