In a Win7 computer that belongs to a domain, how do I append DNS search list entries?

I found a way to do this which is probably a workaround and which won't work on a locked-down box where you don't have admin rights. Edit the registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\DNSClient\SearchList

Add to the end of that key any domains you want to add to your search list -- although this key may entirely replace your search list. This list should be comma-separated with no whitespace.

After making the change, you have to renew your DHCP lease as a way of getting the DHCP client to run so you can apply the change:

ipconfig /registerdns

Once you have done this, you'll have the new entries in your DNS search list.