[ONE Q&A, Help & Troubleshooting] TheROMGuy:
Try uninstalling the drivers and plugging your device in and see if device manager shows anything at that point. Make sure to follow it like this. Don't install the drivers before hand just extract them to your desktop.

Once you have the drivers straightened out, connect your bricked phone to the computer and start it up by holding VolUp + Power to about 10 seconds, and let the computer do its thing. Don't install drivers if they are not installed by itself. Instead launch Msm8974DownloadTool.exe as Administrator (right click on Msm8974DownloadTool.exe and select "Run as administrator") from the extracted Color.zip archive. It will scan all the COM ports and find the phone. That's the one line that looks different in the list. The list is just a list of your com ports and devices. If you unplug the phone and move it to another port, it will show your bricked phone on a different line.

Clicking on "Enum" just rescans the busses. Clicking the big square button in upper right corner scans the phone and reports what's good and what's not. It takes a minute for the scan to finish.

If you don't see your phone in the list of com devices, try unplugging/plugging in your phone a couple times, and rebooting it with VolUP + Power (hold 10 seconds). You will see it in Device Manager as well.

Once you see the phone in the list, click Start. You should see the programs start writing different files to the phone. Each time it writes a file you'll see a progress bar. Once you see this process happening, smile, you know you will be good to go... After all files are written, the com line with your device will turn green. You're good, unplug and reboot your phone. It will boot to ColorOS, the Chinese OS that comes on OPO.

source: http://xdaforums.com/oneplus-one/general/guide-unbrick-oneplus-one-t3013732

---------- Post added at 03:32 AM ---------- Previous post was at 03:13 AM ----------

This is all I can think of to do. If you're going to use the XP Machine. install the drivers using this.

Go to the extracted Color.zip folder and find Driver.iso. Extract Driver.iso. Inside the extracted folder find Setup.exe. Run Setup.exe to install the drivers. The installer is Chinese, but all you need to do is click through the prompts.

Then follow this word for word.

Once you have the drivers straightened out, connect your bricked phone to the computer and start it up by holding VolUp + Power to about 10 seconds, and let the computer do its thing. Don't install drivers if they are not installed by itself. Instead launch Msm8974DownloadTool.exe as Administrator (right click on Msm8974DownloadTool.exe and select "Run as administrator") from the extracted Color.zip archive. It will scan all the COM ports and find the phone. That's the one line that looks different in the list. The list is just a list of your com ports and devices. If you unplug the phone and move it to another port, it will show your bricked phone on a different line.

Clicking on "Enum" just rescans the busses. Clicking the big square button in upper right corner scans the phone and reports what's good and what's not. It takes a minute for the scan to finish.

If you don't see your phone in the list of com devices, try unplugging/plugging in your phone a couple times, and rebooting it with VolUP + Power (hold 10 seconds). You will see it in Device Manager as well.

Once you see the phone in the list, click Start. You should see the programs start writing different files to the phone. Each time it writes a file you'll see a progress bar. Once you see this process happening, smile, you know you will be good to go... After all files are written, the com line with your device will turn green. You're good, unplug and reboot your phone. It will boot to ColorOS, the Chinese OS that comes on OPO.

source: http://xdaforums.com/oneplus-one/general/guide-unbrick-oneplus-one-t3013732