desk98.exe is a process which belongs to ATI's HydraVision Desktop Manager. This allows the user functionality for setting up desktop behavior in multi-monitor environments.
Non-system processes like desk98.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues