Hi, i have the Arduino Nano and suddenly i can't upload (to the nano, from PC) any streams on Windows anymore. On someone else's computer it worked however, letting me feel rather stupid :0 (dunno which OS). Anyway suddenly it doesn't work on vista, but it works on that same machine in ubuntu (dualboot)!! This worked for me until my PC died, and now i have Win8 on a new machine, no linux.
Only on windows, during upload the rx led is flickering with lower intensity than it should, tx doesn't light up. The IDE console says it sends but isn't receiving anything from tx (not in sync). i know there are trillions of posts about that error message but in my case, it works on linux so i can tell u the board is working, as well as the usb cable(s), the USB ports, the drivers, the code, the port selected, the board selected, ...!
U guys might not give me a fix but i don't even know where to look or what to search next to fix it 
so pleeeaase give me some hints. Also, i made a fresh install of the IDE on another PC, dualboot, and had that same OS dependent error as described before.
I tried it on a virtual machine but messed up the port configurations, so i am giving it another try..
(btw i also noticed that the ide compiles faster in linux than in windows, but that's another story :%)