Lisa, here's the law in Ohio.
http://codes.ohio.gov/orc/2913.11
http://ohiohomeownerlaw.com/2013/02/21/ohio-bad-check-law-dos-and-donts/
http://www.columbuscriminalattorney.com/theft-fraud-crimes/passing-bad-checks/
What amount was written on the face of the check?
If this is a first-degree misdemeanor, there is a two-year statute of limitations under Ohio law.
If you have received a REAL summons in the mail or have been arrested, you should hire a criminal defense attorney who can draft a good motion to dismiss on statute of limitations grounds.
If it's a higher misdemeanor or felony, after 18 years the SOL most likely has expired.
If this involves a bench warrant after being arrested and released on bond, you might have a bigger problem. That's a BENCH WARRANT, and they just don't age away and die.
I suggest you contact a local attorney and discuss this with him or her before you do anything or speak to anyone.
The initial consultation is normally free of charge.
If this is coming from debt scavengers, more than likely you're being scammed.
You'll know for sure AFTER discussing this with a local attorney.