IRS help

For tax year 1999, I did not file a tax return. I did have multiple jobs, but can only find 3 of the 4 w-2's. On the ones that I can find, my income was not even over $1000. What is the wages requirement for actually having to file? I did have taxes taken out on the amount that I did make and I am sure that on the 4th job I had taxes taken out as well. I do not think that I would end up owing any money during that year and have not received (to my knowledge) any notices from the IRS about any taxes that I may/may not owe or about not filing a return that year. What should I do about this? I am scared sick that if I call the IRS or open any type of inquiry that I will be penalized. I have also not had any type of lein placed on my credit record or anything like that. I do have a bank acct. and no money has been garnished from it, etc. I know that logically I should contact the IRS, but what if my income was not enough to have to file that year or what if I didn't owe any money to the IRS, but was entitled to a refund that year? I couldn't collect the refund because the time has expired to be able to. What should I do?

See: HR Block Tax Advisor link --

http://www.hrblock.com/taxes/product...p?productId=44