Help Windows 7 Ultimate

Hi! good afternoon first let me put some thing about my computer, I have 4 computers, LINUX, WINDOWS Vista, Windows XP and Windows 7.

All machines work very well arduino uno, but with windows 7, happen this:

The drivers that i install it's drive:\arduino-0022\drivers, all pass ok!
I look in my pc and see:

ARDUINO UNO (COM3)
Version del controlador: 5.1.2600.0
Fabricante: Arduino LLC
No problems detect.

In c# or Arduino IDE, I can open and close the port. But, when i write a byte in port COM the ARDUINO UNO don't response, in Windows XP Work, in Linux Work, and Windows Vista Works! but in Windows 7 Ultimate edtion Version 6.1 build 7600. dont work!

It's any problem with the driver?? What i can do for work this?

Thanks a lot.