~ap3.tmp is a temporary file that belongs to Microsoft.  It is used in the MPEG-4 codec that is used with Windows Media Player.  In other words, it is what lets you play certain kinds of videos in Windows.

~ap3.tmp and other files like it work inside the Windows registry.  The Windows registry is where “shortcuts” to software and hardware run, so that they won’t take over the entire computer every time they operate.

It is no fault of the owner if the directory gets damaged, cluttered, or out of date.  Frequently, the directory gets all three!

Sometimes directory entries are damaged or faked by virus or spyware programs.  Other times, software programs and hardware drivers don’t uninstall properly.  And some programs don’t delete their old entries when they update, but rather leave those registry files still using processing power without actually attaching to anything.

The least expensive and most thorough way to take care of these problems is to run a registry scan.  ZookaWare PC Cleaner offers a free scan so that you can see what slows down your computer.