Temporarily Disconnect Drives

Win XP and / or Win 7 and ...

Many times I will be away from home with a desktop or one of many
laptops and run into this.

Apps starting up will get bogged down trying to access disconnected
drives e.g. NAS pen, memory stick. Al assigned drive letters.

I have seen the network get bogged down because the app is flailing the
network trying to access a NAS. I have to disconnect it to stop it.

Is there a way to temporarily tell Win not to include those drive
letters in any search or whatever ?

Disconnecting them means have to go through the process of connecting
them as drive letters again.

is this just bad Windows code ? !