Dear friends, I am running PPC campaign over yahoo, my question is that tracking pixel from my site got deleted somehow, if I do replace the pixels again then will I be able to get conversions from my old cookies or not as there is no change in tracking pixel.
You need to go get the tracking code from the Yahoo interface and place it on your Thank-You page. You will not be able to get your past conversions, there is no way that they were tracked without the code on the thank-you page.