catalyst control center :host application has stop working

This may be the solution you are seeking.

I recently removed the Vista Recovery Center malware from another one of our company laptops. It has ATI graphics installed. This malware hides most of the files on the PC in an attempt to fool you into thinking that your PC is really damaged like it is reporting. Removing the malware does not undo the hidden aspects. In Vista, the c:\Users\"your profile name (usually Owner)"  folder contains the AppData subdirectory that the Catalyst Control Center needs to access in order to function. When this directory is hidden, then CCC cannot locate the necessary files to launch. To fix this issue, I use the following steps.

Navigate to c:\ and right click on Users. Select properties. Under the General tab, look at the bottom for the Hidden selection. If there is not a check mark in the box, place a check mark there. Hit apply, select yes to apply to all subdirectories. If you clicked ok, you may notice that it disappeared from the right pane once it finishes. It should still be listed under the tree on the left. Right click on it again. This time remove the check mark and apply to all subdirectories. Once it has finished, your files in the Users directory should reappear and Catalyst Control Center should function normally again. This has worked in all cases that I have encounterd so far. Hopefully this works for you as well..