TV TUNER

I have a dell XPS 410 XP running Media center 2005-roll up 2
After a year of fine performance, my pc suddenly tells me that my tv tuner is not installed.
I checked connections, reinstalled a new driver, came to the conclusion that the tuner had gone bad. I put in a new tuner with new drivers and the same window came up...tuner not installed. With the tuner in the computer, on start up you get the same message over and over. So I took the tuner out. I have seen many people on the web describe the same problem but I haven't found a solution. Can someone help?