COM ports not listed in Device Manager

[Designware]

Hi,

I have tried to search for an answer to this question. The only thread I found was thread779-601205, but it never had a resolution. Googled as well.

I have no COM ports listed at all in the device manager. There was a modem working on this PC a week ago (using COM3). The modem no longer works, and COM3 (COM anything) is gone. All it lists are the LPT ports under that category.

I try to add new hardware, and it finds nothing. I looked in the BIOS and couldn't find anything re: the COM ports. (That doesn't mean it's not there, I just couldn't find it. I 'll look some more too.)

Operating System is Windows Media Center.

Thanks in advance for your help.

 

[DTracy]

Check the CMOS to see if they have been disabled.

 

[Designware]

In CMOS, under I/O device configuration (where I assume the serial ports would be), there is nothing listed except:

Parallel Port Address 378
Parallel Port Mode ECP
Parallel Port IRQ IRQ7

I have also looked everywhere in the BIOS I can go to find some serial port settings. No luck.

Thanks for the reply.

 

[DTracy]

The modem may be dead, have you tried a replacement?

 

[bcastner]

Is the plug and play service running?


____________________________
Users Helping Users

 

[bcastner]

The COM ports are PnP Devices with a PnP enumeration number of PnP*0501

See what you have in your Registry at the following location. If empty, copy/paste the below into Notepad and then File, Save as, fix_com.reg :

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM]
"\\Device\\Serial2"="COM3"
"\\Device\\Serial1"="COM2"
"\\Device\\Serial0"="COM1"

Double click the saved "fix_com.reg" to merge with your registry. Reboot and investigate Device Manager again.


____________________________
Users Helping Users

 

[linney]

A lot of the DOS still works in XP, see if you can make use of this article?

Troubleshooting Serial Port Problems in Windows

http://support.microsoft.com/default.aspx?scid=kb;en-us;105940&FR=1&PA=1&SD=HSCH

See if these lead anywhere?

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Ports

Search the Registry for COMn (n = number) and see what else you can turn up.

Does the Properties of your Modem (Device Manager) show a COM Port being used (Properties/ Modem)?

You might solve your problems just by using System Restore to go back a week in time?

 

[Designware]

Thank you for all the replies. This one is my error. I did not know that logical COM ports do not show up in the device manager in Windows XP.

DTracy, you were correct. It was simply a dead modem. A new one did the trick.

Bcastner, thank you for responding to so many of my inquiries. FYI, I went into the registry and here is what I've found (this is after I installed the new modem, so the COM port listed is COM4.) The reason that there's no COM1 is that this PC does not have an old fashioned serial port on it.

[HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\SERIALCOMM]
"\\Device\\SmSrl"="COM4"

Linney, thanks for your responses as well.

New modem is working.