usb blaster for windows 7

hi
i have installed Quartus II subscription edition version 8.0 for windows (platform supported windows vista,xp, 2000) on windows 7 operating system...i tried some project in vhdl which works fine.....but when i am trying to use altera DE2 development board USB blaster is not getting installed
i downloaded usb blaster drivers for windows 7 which is not getting installed.
please tell me what could be the problem......
1. should i change my windows 7 os to XP

THANKS