My Gigabyte GTX260 will not show Temps

i have tried installing loads of diffent software to detect temperture for my gtx 260 but none work i can still run games etc.. also i have a 9600gt plugged in aswell and that shows the tempertures but not my gtx260 .

i think this is the model [color=#000000; font-family: Arial, Helvetica, sans-serif; font-size: 13px][b]Gigabyte[/color][/b][color=#ff0000] GV N26OC-896I Graphics adapter - 896 MB - GDDR3 SDRAM[/color]

I've had that issue, uninstalling Nvidia drivers, cleaning them with driversweeper, and installing the latest drivers fixed it for me.