Is there a statute of limitation (in years) when dwi's may be dropped in Austin, Texas?


Optional Information:
monroe, Louisiana

Already Tried:
i was told that after several years, a dwi charge could be dropped. i never went to court over it so, have not been sentenced. dwi was about 8 years ago. i do not drive and have not in all this time. but i iwould like to get my driver's license some day. but i can't because a 'flag' from texas. what do i need to do, who to ask, to see if this old charge may have been dropped.