Computer won't boot up

Hello,
For about a month, our Compaq Presario SSRS410F has periodically given us a message about a bad disk sector, but when I run the diagnostics, it says all is fine. Then it started periodically not booting up, but if we tried again, it would go ahead a boot. Yesterday, it booted up, but for some reason I can no longer remember, it said I had to restart my computer. I have not been able to get it to boot since then. It keeps giving me a message that says "Boot Disk Failure" When I repower it, I hear a whirring sound and it gives the compaq screen and then a blank screen and then I get the above message. I wondered if it might be a bad power supply not giving enough juice, so I looked on here and saw that first I shoudl try cleaning it and reseating the memory cards. I did that and got continuous beeping. Reading more on here, I determined that meant I needed to use the compressed air (I hadn't had that when I "cleaned" it, so I bought some and tried again. Now, I am back to where I started. Do you think I should try replacing the power supply?

For the configuration below, it defaulted to this machine. The machine with the problem is a Windows Vista Home with Internet Explorer 8.0 (I think that is the right version)