Microsoft Registry Tool – REG.EXE
Most commonly, reg.exe installs as a part of your Windows operating system. It can be used to query your Windows registry and lets you read, set, or delete registry keys and values. It is similar in function to the regedit tool with one exception, reg.exe is a command line utility.
Typically you'd find this file on your Windows 98/NT/2000 resource kit. It appears to be included with a normal install of Windows XP. If you're running XP and having problems with this file, Microsoft describes a fix at http://support.microsoft.com/?kbid=823468.
It is not normal for this program to need to run on system startup or to be running all the time. If you find that it is and know that you didn't start it yourself, there's a chance a malicious program may be using it to modify your registry. Only in this event would we recommend removing this file using WinPatrol. Try killing it under Active Tasks then disabling it under Startup Programs.
Safe
Microsoft