So this is more a social/political issue and has been discussed a lot in the past here - mainly about stopping services etc... Sounds like the user is a local admin on the machine, so there is not a lot one can do to prevent this.  I would pursue this along the lines of a more political avenue. Does your company currently have a computing policy? This would NOT prevent items like this from happening, but would provide leverage on how to address these types of issues - disciplinary actions, etc...  The employee is doing this action because there is no accountability and recourse. Even if LANDesk provided a password on the uninstall it would be somewhat easy to disable/uninstall the client. Unless you implement a NACish solution, you will always be behind the 8 ball.

So I would torment the hell out of the employee. You could impliment a windows scheduled task that checks for the client and reinstalls - with a reboot, or use a login script that reinstalls the client when not found - with a reboot.  They will get tired of this since it reboots, and your solution is an automated one and the user will have to manually uninstall the client.  I would also pursue this with the user's management.

Have not tried this (from Mitch):

We have the same issue. My fix was easy. Group Policy.

I set all LANDesk services to automatic/started and only allowed one user (LANDesk global admin acc) to be able to change them.

Not mine - sorry. They wont let me play with GPOs in my shop.  Got it from Mitch on this post:

http://community.landesk.com/support/message/15090#15090