runXT is a replacement for the standard windows run dialog.
It supports custom commands which can be created using the built in GUI or manually via XML.
It also features Hotkey and Tray Icon support, an built in calculator and time display when in standby mode.
runXT is pretty small and should run on almost any computer running Windows 2000 or higher. You just need Microsoft’s .NET 2.0 Framework.
Download: runXT 0.4