Stage two dementia is an early phase of the syndrome in which people exhibit very mild cognitive decline, possibly including some memory lapses.
Windass said it was "emotional" for him when he underwent tests and although he doesn't know what the future holds, said he was trying to live as normal a life as possible.
He added: "There's nothing I can do. You can't roll back the years, so you've just got to deal with it as much as you can.
"Hopefully, in the next five or 10 years it doesn't develop. It might do, but it might not. So, you get up in the morning and you live. You try to live your life as normal."
Windass was part of the Bradford City side promoted to the Premier League in 1999 and wrote his name into Hull City folklore with the only goal in the Championship play-off final at Wembley in 2008.
He also had stints at Aberdeen, Oxford, Middlesbrough and Sheffield United during a career that saw him amass more than 700 appearances and score more than 230 goals.
"If they'd said [when playing] that in 10 years' time you might have a shade of dementia. I'd go 'well I'm not heading that ball then'," Windass added.
"I wouldn't have done that as much in training… [I'd] probably think twice."