USB Serial Adapter - failure to install

I have been using a Targus USB - Serial adapter (model PA088) on by laptop for some months. Then the notebook refused to access the adapter as a serial interface. When I tried to re-install the drivers (after deleting any that were lying around), the New Hardware Wizard always came displays the message:

  There was a problem installing this hardware.
  USB Ver1.2 Device
  An error occurred during the installation of the device.
  Access is denied.

I tried using a different USB Serial adapter (Prolific) but with the same result.

All 4 USB ports on the laptop work with a mouse, keyboard, memory stick and webcam so I presume the hardware is OK.

From what I have done so far (see 'What I Have Done' below) it would appear that there are old registry entries referring to the USB Serial adapters and that these may be interfering with the re-installation.

I don't want to go to the trouble of performing a clean installation of Win XP since the problem may happen again and I need a proper solution.

Machine Info:
The laptop is a Hi-Grade M6600 with a Pentium 4M 2.5GHz processor.
The machine was pre-installed with Windows XP Pro SP1 and I have added all the latest security and driver updates.

What I Have Done:
(1) Deleted all USB device drivers (including invisible devices) via Device Manager (so that only working/connected devices would be re-installed).
(2) Re-installed Win XP (in-place upgrade).
(3) Tried to delete various USB Vid_* registry keys (as mentioned in Some were deleted, but not all. Some of these are referring to unknown devices, possibly the USB Serial adapter.
(4) Tried deleting those keys while if 'Safe' mode.
(5) Tried new drivers from Targus.
(6) Searched the MS Knowledge Base for related problems.
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Try removing hidden drivers in device manager and then reinstalling.

 Click Start->Run->CMD

 Type the following lines exactly from the command prompt (misspelling won't generate an error):


 In the window that opens, Click View/Show all hidden devices.
 You should see ghost or transparent icons here that identify any drivers that have been left behind...
 Find your hardware and delete it from this list.

 Reboot and allow windows to reinstall the driver.

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Have you looked at the entries for USB controller hubs in device manager for power saving, and unchecked the feature?  The USB ports may be powering down, to conserve energy.
Try Sirbounty's exellent idea, and if you still have no joy,

Also check the values at:
HKLM\Software\Microsoft\Windows NT\Current Version\Winlogon

Look at the values

If these are set to 1, you may not be able to access removable devices under certain condidions.  Try setting these to 0 (or deleteing them), and restart.
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alanolwayAuthor Commented:
Thanks for all your replies (I have just subscribed to the service and am very impressed).

Sirbounty Comment:

I had seen something like this from browsing Experts Exchange earlier today but I had forgotten to select View -> Show Hidden Devices. This did show up a number of other USB devices including the malfunctioning serial driver (I deleted every USB device such as my mouse and webcam devices). Unfortunately, I was still not able to re-install the USB Serial adapter. However, since your reply seems to be so relevant I will continue trying this approach.

Callandor Comment:

Yes, I had seen that in Experts Exchange and tried it but with no success (I forgot to include it in my 'What I Have Done' list).

YarnoSG Comment:

I will try your reply out in a moment.


As a general point, is it likely that the problem is because of all the old USB Vid_* entries in the registry?

Is it possible that the USB Serial adapters are either not working correctly or incompatible with my USB ports? I have heard rumours that USB Serial adapters are some of the most unpredicatable devices to attach to a USB port.
alanolwayAuthor Commented:
YarnoSG Comment:

Have just had a look; the registry has a value of 0 for the settings you mentioned (though my registry shows allocatedasd rather than AllocatedFASD, was that a typing mistake?).
(Mental Typo). AllocateDASD is what I meant.  
Cleaning up the "Ghosts" using the DevMGR_Show_Nonpresent_devices + Show hidden should clean up the stray registry entries you mentioned.
"I have heard rumours that USB Serial adapters are some of the most unpredicatable devices to attach to a USB port."

Yes, it is not a reliable device and many have reported problems getting them to work.  It is far better to remain in the serial domain from start to finish, if one can.
alanolwayAuthor Commented:
I have not had any further progress with this (other software development activities have taken priority). However I will continue to try and fixed this without reverting to a clean installation of Win XP.
I do need to understand the problem since most laptops no longer have serial interfaces and, for convenience, we are using laptops to access low-level engineering interfaces (serial) in our products.  I certainly don't want to have to live with re-installing Windows every so often especially as we have had problems on more than one laptop.
Perhaps there are other ways of providing a serial interface on a laptop (changing our engineering interface is not an option).
Where I am at the moment is that:
(1) The USB Serial adapters I am using will install OK on other PCs (mostly Dell desktops but also home built).
(2) We have had problems on some other laptops (can't say if it is a solely a laptop problem; shouldn't be since all forms of PCs should be compatible).
(3) With my own laptop, sirbounty's proposal for deleting the existing devices does remove all the registry entries. I also deleted all the USB devices, including some for internal mass storage devices, so that only the necessary ones were re-installed on restart. However still no luck.
I will keep you posted. Thanks for your comments so far.
alanolwayAuthor Commented:
I have had some success.

I have been able to install the Prolific (Model 2303) USB Serial adapter using the latest drivers (available just a few days ago).

I still cannot install the Targus USB Serial adapter on my laptop though it installs OK on other PCs.
alanolwayAuthor Commented:

I have decided to use only the Prolific USB Serial adapter. It has benn working reliably over the last few hours. The Targus adapter, even when it was working, always had re-connection problems. Often, I had to disable then re-enable the device.


Thanks for all your comments; they allowed me to reach my solution by a process of elimination.
Jaime OlivaresSoftware ArchitectCommented:
I have a Targus USB Serial adapter also. Initially had no problems connecting the cable to the laptop  but I had strange results when connecting firs the cable to a GPS device and then to the computer, sometimes was recognized as a USB mouse.
My conclusion is: always connect usb cable first to the computer and later to your data device.

Effectively USB cable can have strange behaviors when computers wake up from hibernate or sleep. I recommend you to buy a PCMCIA card instead. For industrial applications you can find the Socket Rugged PCMCIA-Serial adapter in
alanolwayAuthor Commented:

I had also wondered if some of the problems were because of the hibernate/sleep mode of the laptop.  However I have found that the Prolific USB Serial adapter (with the latest drivers) is very dependable and copes with the hibernate/sleep modes well.

I have given up with the Targus adapter, especially as some colleagues have also experienced problems with it (the laptops used included Dell, Sony, Toshiba as well as lesser known brands).

Your idea of a PCMCIA card would certainly bypass problems with the USB Serial adapters.

alanolwayAuthor Commented:
Final Decision:

I have decided to use the Prolific USB Serial adapter with the very latest (16th April 2004) Windows XP drivers from Prolific ( since that is working reliably in my laptop.

Note: I am happy to award points because the answers all helped me towards my final solution and the problem was hindering my work.
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