All sales that were made prior to October 1, 1977, under deeds of trust to secure debts and indemnify sureties when the notice, advertisement, and conduct of the sale were in accordance with the law of the Commonwealth as it existed on June 30, 1977, are declared to be valid and effective in all respects, provided that nothing in this section shall be construed as affecting any final order entered prior to March 23, 1978, by any court of competent jurisdiction, or any action now pending in a court of competent jurisdiction, or as affecting intervening vested rights, and provided further that no action to vacate or set aside any such sale may be brought after March 23, 1978.