@PinKLip
In most cases, any BT dongle can be used with any BT software to communicate with any* BT device.
*Provided the device has support for the required BT profile.
Almost all USB 2.0 Compliant devices support older USB 1.1 standard too (unless stated otherwise). So, I don't think it's a compatibility issue.
Try this: (order of steps is important)
1. Disconnect your BT dongle.
2. Uninstall all BT softwares. BlueSoleil, Float Mobile... etc.
3. Uninstall any remaining USB related devices in Device Manager under "Bluetooth USb", "Human Interface Devices", "Network Adapters", "Ports", "Sound, Video ...". In most cases, when we uninstall BT software that came with the BT dongle these are uninstalled automatically.
4. Restart PC and Install *"the software that came with"* yout BT dongle. If you didn't recieve any, you can install BlueSoleil. That's what I use with my K700i without any problems.
5. While installing BlueSoleil you may observe that dialogs are being dismissed automatically. That's normal. If you get a dialog that says something like "This driver has not passed Windows test..." install it anyway.
6. Though not necessary I would recommend that you restart your PC here.
7. You'll see a "Network cable unplugged" icon in your System Tray. Start BlueSoleil. When it says "Please insert a Bluetooth device" insert your BT dongle.
8. At this time XP will also detect your BT dongle and ask you to install drivers for it. Click on "Automatically install drivers..." and since you have BlueSoleil already installed, XP will find all the drivers automatically from system directories.
9. BlueSoleil's icon will turn blue in color and "Local Area Connection" icon with a "Red X" will dissappear.
10. That's it. Your Bluetooth is installed now!
Now just pair your K700i with your PC and transfer your top 10 Mp3s on to it.
Why? Because the sound quality with the bundled Sony's stereo earphones rock!!