We have split the Sony Ericsson unlocking instructions into two parts
Part 1 - Driver Installation | Part 2 - Unlocking Instructions
Download the Sony Ericsson Unlock Software here
Download the USB Cable Drivers here
Extract both files to a folder on your desktop.
Connect the supplied usb cable to the PC. The found new hardware wizard will appear. Click on No, not this time and then press "Next"

Now select "Search for the best driver in these locations" and then click on the "Include this location in the search" and click on Browse. Scroll to the directory where you have saved the Totalserver drivers and press "ok"

On the screen below select "continue anyway". This is a common warning with Microsoft XP and it only signifies that Microsoft themselves have not confirmed compatibility with the drivers.

The "Files Needed" box will then appear as on the image below. Simply select browse and double click the ftdibus.sys file that appears in the window that pops up.

The completed installation window will appear shortly afterwards, just click on "Finish"

The "Found New Hardware Wizard" will appear again. Click on "No, not this time" and press "Next"

Select "Install from a list of specific location (Advanced)" and press "Next"
Click "Continue Anyway" as before

Click the "browse" button and double click on the file "ftser2k.sys" that appears in the window that pops up

The completed hardware wizard screen will now appear. Just click "Finish" as before.

Now you need to go into your control panel to see which port the computer has installed the cable onto. You can reach this from the start menu and then selecting the control panel. A screen similar to the one below will then appear. Double click on the one called "System"

Select the "Hardware" tab and then click on "Device Manager"

Go down to where it says "Ports (Com&Lpt)" and make a note of the number it has next to the COM. Ie, in the case below it says (COM24)

Click here for Part 2 which contains the unlocking instructions