With sufficient compensation and being under 70½, you are eligible to contribute to a regular traditional IRA but your MAGI might limit your eligibility to deduct the contribution, depending on whether or not you are covered by a workplace retirement plan.
With regard to your businesses SEP, plan, if your business established a SEP plan and never terminated the plan, your business still has a SEP plan (although it might be necessary to update the plan agreement if it hasn't been updated since 2004).
