My computer will not enter standby mode

[Guest]

When I try to put my computer on standby the following message appears: "The
device driver for the Communications Port (COM1) device is preventing the
machine from entering standby. Please close all applications and try again.
If problem persists, you may need to update the driver."

I believe I need to install an updated driver for my display adapter.
However, I am having difficulty locating an appropriate download (for no fee,
if possible). Could someone point me in the right direction?

 

[Guest]

I forgot to mention that I am using Windows XP Home Edition; SP2