I recently upgraded my Y300 from Vista(which is factory pre-installed) to Windows 7 Home Premium(which is a clean install). Previously, when my Y300 was in Vista state, I already have the abovementioned problem. In which, there'll be an exclamation mark on the device driver in Device Manager settings. And from that moment on, my Energy Cut software wasn't working anymore. It's the same problem here with Windows 7 and Energy Cut software doesn't seem to be running even after I installed it from the provided CD-ROM driver. I'm afraid it's affecting how my Y300 behaves when it comes to power management, battery life, so and so forth.
So, if there's anybody out here with any workaround to rectify this problem will be greatly appreciated. But other than that, my Y300 seems fine with Windows 7. In fact, it runs faster compared with Vista installed. Thank you, guys.