Bluetooth headset pairing failed, worked previously with same hardware

I am trying to get a Bluetooth headset paired with a Windows XP computer but
the process is failing.

I'd previously gotten the headset and computer to pair with no problem, but
the hard drive had to be re-imaged by the manufacturer because of some
intractable problems fixed by this re-imaging. However, when I tried to
pair the headset with the computer, something went wrong and I don't know
how to recover from the problem.

I did the pairing with the headset charged and unplugged. When I first
tried the pairing I had to look up the passkey, and something seemed to time
out so I started again. This time I entered the passkey and for some reason
I was told that I needed new drivers, which I think is wrong because the
Toshiba drivers on the computer are supposed to be all I need. I got
offered a Microsoft driver from the Web along with a warning that it would
be dangerous to install the driver. I declined the driver, and at some
point soon after the Add New Connection Wizard hung. After 10 minutes I
terminated the program since it was not responding.

Now when I try the pairing by putting the headset into pairing mode and
using the Add New Connection Wizard I see: "Searching for Bluetooth devices"
followed by:
"PLT 510 v.G"
appearing under "Device Name" for "Bluetooth device". After clicking on the
device I get a message:
"Now connecting to your Bluetooth device. If an Authentication is required
a dialogue appears where you need to enter your Pass key (PIN code) for the
Bluetooth device".
In contrast to my original attempt, no Pass key request comes up but soon
there is a message:
"Connecting to remote device. Please wait...".
This in turn is followed by a Dialog saying:
"Connection failed".
Throughout the process the headset is flashing its red and blue code for
being in pairing mode, the computer's WiFi radio is off and the location's
WiFi signal is turned off.

It seems that the computer is in some state in which something is corrupted.
I've tried reinstalling the driver from the drivers CD (in Device Manager
uninstalling and re-installing the network adapter "Bluetooth Personal Area
Network from TOSHIBA" and then scanning for hardware changes and letting it
reinstall the driver from the CD) but this didn't result in any change.

At times I've been able to coax the system into a state in which it says
"connecting to voice circuit. please wait" but it never connects. At one
point I got a "Headset functions not supported in current hardware
environment" message but I haven't seen the message again.

Is there some way of getting out of this rut?

Details:

Headset = Plantronics Voyager 510 (Plantronics said they don't offer support
for headset issues if they involve computers).
Computer = Motion Computing LS800 running Windows XP Tablet PC Edition 2005
(SP2)
Bluetooth on computer = Bluetooth Personal Area Network from TOSHIBA with
Toshiba 5.0.2129.0 driver

I was able to solve this by using a Restore Point. Windows Defender seems
to make a huge number of restore points and this allowed me to go back to
the exact point I needed.