Arduino Not Recongnized by Computer

About two months ago I bought an Arduino UNO and started using it with my laptop with no problems. It's been a few weeks since I've used it and now when I plug it in the laptop does not recognize it. I looked on the forums and it seems that reinstalling the drivers should have fixed the problem but when I try to upload a program to the board I get this error message: "avrdude: stk500_getsync(): not in sync: resp=0x00". If anyone has any suggestions for how to fix this problem they would be greatly appreciated.

-Steve

When you connect the UNO to the USB cable, does it make the device connect "sound" on your PC?

Yea it makes the sound that it recognizes something is plugged in, but when I go to the device manager it is listed as "Unknown Device" under the "USB controllers" tab.

See if you can change the COM PORT. Should be in the "Unknown" Device -> Properties -> Settings Tab -> Advance...

Change it to something something greater than COM4 (and unassigned). Some other virtual com port may have hijacked you Arduino COM PORT.

If it is listed as a Unknown Device in Device Manager, then you need to install the drivers again.

Here are the steps:

Right click the Unknown Device in Device Manager
Select Update Driver Software
Select Browse my computer for software
Click Browse button
Select the Drivers folder under the location of your Arduino software installation. (Do not select the FTDI folder inside the Drivers folder)
Click OK
Click Next

I got it working. I'm not sure what was wrong but I ended up unplugging everything that was plugged in and tried the Arduino in every spot. Eventually after reinstalling the drivers it worked in one of them.

Thanks everyone for the help.

For Windows:
First: make sure you have current version of Arduino and note the location of the DRIVERS (very important).
Second: check that you have selected the correct board type in Arduino IDE- Tools.
Third: when you plug in the Arduino via USB, the "found new hardware" wizard should appear. There is an option for where to look for the driver. Direct the browser to the exact folder and you should be good to go.
I spent a lot of wasted time because I thought I had directed the driver browser to the correct file when in fact I had directed it to a higher level folder.
Also: try uninstalling the device from the device manager and then plug it in again to get the hardware wizard to appear.

miguel_rais:
For Windows:
First: make sure you have current version of Arduino and note the location of the DRIVERS (very important).
Second: check that you have selected the correct board type in Arduino IDE- Tools.
Third: when you plug in the Arduino via USB, the "found new hardware" wizard should appear. There is an option for where to look for the driver. Direct the browser to the exact folder and you should be good to go.
I spent a lot of wasted time because I thought I had directed the driver browser to the correct file when in fact I had directed it to a higher level folder.
Also: try uninstalling the device from the device manager and then plug it in again to get the hardware wizard to appear.

First: http://arduino.cc/forum/index.php/topic,118440.0.html
Second: click next :smiley: