No boot device available

I have EXACTLY the same problem as was stated here: http://en.community.dell.com/support-forums/desktop/f/3514/p/19290726/19539664.aspx

I am running the same computer, a Dell Inspirion 531 with Windows Vista home premium (32-bit, I guess)

History: I aquired this computer from my sister about a month and a half ago. She was having trouble with it where it wouldn't boot the OS, and so in short, after trying a bunch of tests and such, I just saved all her pictures and music to CDs and did a clean factory image re-install. After that finished, I updated everything VIA Windows update (SP1 was a pain, but I figured it out) and fixed problems like sound not working and such. After that was done, I installed only 1 game, and networked it with my Dell Latitude D610 laptop (running Windows XP Pro) so I could play other games and music without having to transfer a stock pile of music and programs, and bog down BOTH computers.

About three days ago, The computer started to run slow while watching videos on Youtube, even though I only added that one game. So I cleared my history, cookies and stuff, and kept going. It worked for a bit. But then when I put it in hybernation mode, I tried to bring it out of hybernation mode the next day, and it gave me a BSoD error, including the file "win32k.exe" I believe it was. I didn't copy it. Anyway, I rebooted, and it booted properly, but very slowly. So I rebooted again to see what would happen. I got this error:

"No boot device available

SATA 0:Installed

SATA 1:Installed

SATA 2:None

SATA 3:None"

I tried a bunch of things, including disconnecting the data cable to the HDD and changed it from the "P3" to the "P4" port of the cable, which a few things, like this, worked. But only temporarily. I've also recently recieved other error messages, like "Could not boot OS properly" or some such. But now, it's mostly been the above meantioned error. Now nothing I try is working. I've tried making minor changes in Bios, like whether to enable or disable "HDD Smart" and the Boot Device Priority, making the HDD the first boot device, and other such changes, as well as loading defaults when all those changes failed. I also tried to boot to the diagnostic partition (since it HAS the partition, and not a CD), and it says the same thing. I tried pressing F8 to try and see if I could get those options to come up, but they don't.

Other info: I noticed some troubleshooting questions in the other thread, and would like to address them here so that we don't have to go over all of this again. Besides, as everyone says, the more info, the better, right?

-No, I do not believe the HDD is recognized in Bios. Example: In the "HDD Group Boot Priority" screen, it says "1. 3rd Master:" With nothing after that, even with the HDD being on the "P3" port of the data cable (if that even makes a difference).

-Beeps and lights: Some times, there are no beeps, and some times there is only 1 beep, which is the way it should be. The lights are normal. The power starts out amber for all of half of a second when I push it, then stays solid blue. There's also another light that faintly flickers randomly and rarely, that shows the HDD is "thinking" as I used to call it. While the HDD was not bolted down, I started the computer to see if I could hear it spinning, and...it's very quiet, but I can.

-Like I said before, I tried hitting F8, nothing happens, I tried hitting F12, selected the repair partition, and got the same error.

-When I made sure the data and power cords were attached to the HDD securely, I also made sure the data cord was attached to the motherboard securely. I didn't check the power cord in the power pack, I'd rather not open that, but will if I have to. But with the HDD spinning, I'm guessing it's getting power. lol

-I do not have a CD in either of my CD/DVD drives.

If anyone needs any more info, I'll try to help, but I imagine this should suffice. If anyone can help, I'd appreciate it, and will try just about anything. I just don't want to have to get another HDD, as they can be expensive, and out of my price range. Besides, I'd just assume it'd be just as expensive to get a new HDD than to get a new computer, which I can't afford, and don't need, since I have my laptop. Thanks IF you read all of this...