dexplore.exe is a process relating to Microsoft Visual Studio and gives access to in-built help and MSDN libraries. "This program is a non-essential system process, and is installed for ease of use. "
Non-system processes like dexplore.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