What is it?
Windows On Windows Execution - wowexec.exe
What does it do?
In addition to the 16-bit applications, each NTVDM process includes a heartbeat thread that interrupts every 55 milliseconds to simulate a timer interrupt, and the Wowexec.exe thread, which helps to create 16-bit tasks and to handle the delivery of the 16-bit interrupt. This thread supports 16-bit Windows applications in a 32-bit Windows environment. The WOW subsystem provides an NTVDM where all Win16 applications run. You will see the heartbeat and Wowexec threads when monitoring 16-bit applications.
Microsoft's information page.
You'll want to keep an eye on this google search for any known viruses. The normal location of this file is C:windowssystem32wowexec.exe