how do i open idx files

[7string]

I have these idx files that are contacts i backed up a few years ago. I can not remember which program i used and/or no longer have the software.

How do I open them???

[r8500]

http://www.experts-exchange.com/Databases/Q_20839550.html

[moabtwo]

hi, its 7string logged in with other ID.

Thanks for the link, any free options?