Sometimes when I turn on my homemade desktop computer (running 64-bit Windows 7), the left mouse click and enter key doesn't work. They work well in BIOS, as well as on the Windows 7 BCD and login screen. Usually, restarting the computer solves the problem. Why does this keep happening? I've tried: Using other USB ports Refreshing, repairing and reinstalling drivers Changing mouse settings Refreshing mouse profiles My keyboard is a Logitech G510, and my mouse is a Razer Lanchesis 5600. Both work without problems in Ubuntu 12.04 and Windows 8.1 Preview, and I've been using both on my 64-bit Windows 7 homemade desktop without problems for about a year and a half. I encountered the problems yesterday.