PokerTracker

all the data that i have on the regular players have gone, its like i am starting fresh again

Do you still see your data for these players in the main PT3 window? Have you changed limits recently?

yes the players stats are still there, i did change limits but very briefly

Check that your HUD Options aren't preventing stats from showing, and the FAQ: PT3 HUD has solutions to common issues and a link to how to report your problem for further investigation if it doesn't help.