Unable to access Google account in Android Market on HTC Desire HD
This would indicate that you are not connected to the Internet.

When you did the factory reset, the APN data for your network/carrier might have been erased.

You will have to check with your network/carrier for the correct APN settings.

You can also connect to a wifi network to connect your Google Account.

You can enter the APN settings by going to System Settings-&gt;Wireless and Networks-&gt;Mobile Networks-&gt;Access Point Names-&gt;Menu Button-&gt;Add New.