Before you reinstall Vista, do a simple test.
Can you open the drive using the button early in the boot process?
Shut down, then power on. As the computer is going through POST, press the button.
If it opens, it is a problem with something in W7. If it doesn't, it is the drive.
As to the many problems you have had with your computer, well, the cheaper the computer the more problems you can expect from it. Did you buy it for the price, or for the quality? Because the cheaper the computer is, the cheaper and less reliable the components have to be.