I guess 3rd time is a charm. Generally, a debtor must wait 6 years to file chapter 7 after a chapter 13. The time runs from filing date to filing date. So you should be fine to file a chapter 7 if your prior chapter 13 was filed in 2006. Please verify everything with a bankruptcy attorney in your area.
After filing a chapter 13 case that results in a discharge, you generally need to wait 6 years before filing chapter 7. So from what you've said, it sounds like you can file again.
You need to wait 6 years between the filing date of a Chapter 13 to file a Chapter 7 and get the discharge, so you would be eligible to file a Chapter 7 now. If your only source of income is social security then you might be "judgment proof." You should consult with an attorney to see if bankruptcy is the right answer for you.