My pc can`t recognize Samsung android device and USB debugging is grey

[Android Question]

I was using Win XP and everything worked fine, i could access to my phone via USB. After reinstalling from Win XP to Win7, my pc can`t recognize my Samsung and its only charges via USB. And i can`t turn on USB debugging it is grey. I have installed Kies, samsung mobile phone usb drivers and android usb drivers. I`m using Samsung Galaxy Mini II (GT-S6500D); 2.3.6 android version. And have recently upgraded Kernel: 2.6.38.6-1236311 se.infra@SEI-30@#1.
Btw when i uninstall drivers using device manager and plug in my phone it can`t install drivers automatically.