BleepingComputer.com: Error loading OS

I am getting an "Error loading OS" message on startup after which machine hangs.

I am using Windows Vista Home Basic 32-bit version.

My son was using the computer at the time, so I'm not sure exactly what happened. He says it crashed and wouldn't restart.

Anyway, I have tried various things using Vista boot disk. Tried to use a restore point and I could see them, seemed to work fine through various menus, but problem was not solved. Tried start-up repair but am having trouble locating installation.

I can see the files on the main hard drive using the command prompt, so I know hard drive is not completely dead.

I suspect it may be a virus/malware or something to do with HD.

Anyone have any ideas how to solve this problem?

Thanks in advance.

Let me give some more detail in hopes of getting some help. Here is exactly what I have tried:

1) Boot up computer with original Vista boot disk. select "Repair Your Computer"

2) Get "System Recovery Options" window. Window says to select OS I want to repair, but no installations are listed.

3) Option exists to Load Drivers for Hard Disk, but I'm not sure how to do this. Have inserted Western Digital disk that came with drive but only file that it seems to recognize as file type "Setup information" is Autorun file. Can't change file type in menu from "Setup information".

4) After canceling, and hitting "Next" to proceed through this menu without selecting an OS installation, "System Recovery Options Menu" pops up and I can select "Startup Repair"

5) "Startup repair" seems to work. Log file shows "Root Cause Found: The partition table does not have a valid System Partitition" and then "Repair Action: Partition Table Repair.

6) After this, I hit "Finish" and the system reboots but still have "Error Loading OS".

I'm not sure steps 4 or 5 are menaingful since I am not finding the OS Installation in steps 2 and 3, but am not sure how to find it.

At this point, I am considering getting a new HD and installing Vista fresh on it and recovering what I can off old HD.

Would appreciate any help I can get...

Thanks.

Well, in case anyone has a similar problem, I did manage to get it solved.

Opened up box, disconnected extra hard drives, switched SATA cable for boot HD to different SATA port, restarted and OS fired up fine.

Reconnected extra drives and still works fine. Problem solved.