wow , you are in a tough situation but there really aren't enough facts here.
On the warranty claim you are probably going to be limited to the price of your computer, which is probably around the 1500 they are offering you.
Its a little hard to understand how not paying for a computer "ruined your credit" if you otherwise had good credit.. There may be other issues there for which Best Buy is not responsible.
Finally, Best Buy is not going to be responsible for your depression/health issues under Virginia law, nor are they likely going to be held responsible for your current economic status.
If you do consult with a lawyer, they are going to need all of the documents, including the warranty you originally received.
Finally, you may have a statute of limitations problem since you are talking about a purchase in 2005.