Firstly, I'm writing this after 5 hours of nonstop struggle to make it work, so I searched into the deepest websites from Google, and tried many things.

I have

• Trust Bluetooth 4.0 USB adapter (link)
• Samsung HM1500 Bluetooth Headset
• Windows 7 64-bit Desktop PC

Facts

• Nothing wrong with the headset. (it works, tested on a phone and a laptop. Problem is all about bluetooth dongle and its driver.)
• Trust BT adapter can send and receive files even without any driver.
• I can pair successfully without any driver too.
• In Headset's Properties, Services tab, Handsfree and Headset services are checked.

Problem

When I pair with my BT headset, I cannot see it as a sound playback device. Also when I double-click the headset device icon in Bluetooth Devices,
in laptop: it opens a connection window where I can connect and disconnect to that device - perfect!
in desktop: it opens the properties window, even though Handsfree and Headset services are checked (I check them explicitly, in laptop they came as already checked) - Problem!

Unsuccessful driver installations

• The driver on the Trust's website says "Error 1606 Could not access Network Location" on start, so it doesn't get installed.
• The driver on Broadcom (link) is being closed with Windows's that classic "has stopped working" error on validation step, so it doesn't get installed too. (Those tests made more than once)

Successful installation

In the Win64 folder of Trust's driver from their website, if I install through "BTW.msi", it doesn't give me Error 1606 and it gets installed.

Then the problem: When I try to start bluetooth from start menu (or it gets started at Windows startup), an error popup says: "BtBalloon.dll is missing..." so it doesn't start. I found BBalloon.dll in the driver folder, I renamed it to BtBalloon.dll, moved into Windows/system32 and Windows/SysWOW64 folders, and it seems working. Or maybe it gets closed behind the scenes. The bluetooth icon is there with or without this driver since Windows has it.

Bluetooth Peripheral Device

First it didn't get installed from Windows Update. After, I showed the driver folder path in Device Manager and pressed "Explore in this location". Surprisingly, it's being found as "Handsfree" driver. Now even I uninstall the drivers, it still can see the Handsfree.

But still, no playback device.

Any ideas to guide me? I'm out of ideas.