The employer is out of business and I need to file taxes for those years - how can I get them from the IRS?

Try these steps:
1. Search your home and find out the W2s.
2. Try to get from the employer.
3. IRS does not keep copy of W2. They have it only when you submit it with your tax return. You can still get transcripts of W2 from IRS. Call 1–800–829–3676, or visit the IRS web site at Internal Revenue Service (http://www.irs.gov) to obtain Form 4506-T, Request for Transcript of Tax Return, to order the information from the IRS.
4. You can get copy of W2s from SSA. You have to pay small fees. Call 1–800–772–1213, or visit the SSA web site at Social Security Online (http://www.ssa.gov) for instructions on how to obtain wage information from the SSA.

Even if you have refunds for your 2003 and 2004 returns, you will not get it now. There is three years limit to get the refund. But you must file the tax return, you your income is more than the filing limit.
Read:Your U.S. Tax Return: Missing Forms W-2, 1099-Misc, 1099-Int, 1099-R (http://taxipay.blogspot.com/2008/05/missing-forms-w-2-1099-misc-1099-int.html)

I cannot locate my W-2 from tax year 2004. I need them badly

Call the IRS and ask for your 2004 tax script. You will get it at NO charge and they may even FAX it to you.