Only a portion of my eligibility is available at this time because my prior loan has not been paid in full even though I don't own the property anymore. Can I still obtain a VA guaranteed home loan?

Yes, depending on the circumstances. If a veteran has already used a portion of his or her eligibility and the used portion cannot yet be restored, any partial remaining eligibility would be available for use. The veteran would have to discuss with a lender whether the remaining balance would be sufficient for the loan amount sought and whether any down payment would be required.