1) If you used the TurboTax desktop editions then the only copy of your tax returns will be on the computer that was used for the return. TurboTax does not store online any tax returns created using the desktop editions.
Go to this IRS website for free federal tax return transcripts - https://www.irs.gov/individuals/get-transcript
For a fee of $30 you can get a complete federal tax return from the IRS by completing Form 4506 - http://www.irs.gov/pub/irs-pdf/f4506.pdf
The IRS normally would only keep tax returns for the past seven years.
2) If you start the business again then the depreciation used for the Home Office expense would continue where you left off when the business was closed.
