An inventory scan should make the device show back up in the Console. Ours is set to scan when a user logs in or when the IP address of the device changes. These settings are in the Agent Configuration. You'll have to do it manually if the inventory scan isn't running at regular intervals on its own. On the device in question, go to:
Start > Programs > LANDesk Management > Inventory Scan
Reinstalling the Agent should make the device show back up as well.
If you discover them through UDD you can use the 'Restore client records' scripts under Distribution | Manage Scripts. Just create a scheduled task using the 'restore client records' script, and drag the machines from UDD to the task and run it.
Thanks for all your input. I was able to re-detect the device however I did have to reinstall the agent. Already had the Agent configuration to inventory scan on login. Didn't get a chance to try the UDD method but no doubt will have another one of these to do shortly. I am worried however that we may have a significant number of PC's out there that have been removed on Landesk and not re-detected automatically as they should be.
You may also want to force an inventory on devices using a scheduled task/policy. You can do this only for out of date machines by creating a query based on the 'Last Updated by Inventory Server' attribute. There is a screenshot here on how to specify the number of days since the last update, making the policy more dynamic. This will cause the software distribution client to trigger an inventory, just in case something is wrong with a locally scheduled task for sending inventory updates.
If you are interested in being able to keep a history of deleted machines, you may also want to check out a prodcut called iRecall. With it, you can leave the days to deletion feature enabled, and you will still be able to report on as well as restore deleted devices as their inventory will be kept in an archive database. Screenshots can be seen here .