My laptop (a Lenovo T420 ThinkPad with Windows 7 32 bit) does not recognise my Arduino Mega 2560. There is, however, a blinking red light and a constant red light. I am using a cable to connect the Arduino to an USB port, however no matter which USB port I plug it in, (ones on the left, the back, the front) it always shows up as an USB2.0 Serial under "Other Devices" with a yellow triangle with an ! over the icon, and when I try to install the driver software, pointing it to the arduino\drivers directory, Windows reports that it cannot find any drivers for the software. In the Arduino programming software, I have tried uploading to COM3 and COM4, however neither of these work. I have also tried using my desktop, however it has the same problem. If anyone has any suggestions what to do, or if I need to provide any more information/screenshots, please tell me! (I have tried googling the problem and following their suggestions, but that hasn't worked.)
I have an old arduino mega 2560 and a new windows 8.1 (64 bit) with the exact same issue.
As far as I know it is a genuine arduino and I bought it in a genuine shop. I never had issues with it on xp or linux.
I have 2 devices under "other devices" and when I try to install the driver (I tried both devices with the same result) it states no drivers have been found just like with mvuyk.
The only googled advice I think that may help is the "install unsigned drivers" but that seems a bit harsh to me.
On other versions go into the unknown device and tell it to use a specific driver. Then go and select com port, Arduiono LLC as manufacturer and pick from there.