The Run command on the Start menu lets you run any program by typing in its name and necessary command line parameters. The commands that you run in this way are stored in the Registry. Each time you use a command that has already been stored, it moves to the top of the list. When the list gets to full, commands are removed from the end. The list can contain 26 commands, indicated with a letter from a to z. Thus, the most recently used (MRU) commands stay on the list. If you don't use the Run command, the list can contain commands from very long time ago, dating all the way back to the installation of Windows 95. The list can also contain commands with erroneous parameters or powerful system level commands that you do not want to execute with an inadvertent mouse click.
Modifying the MRU command list can be done by editing the Registry directly. Editing the Registry should be done only by experienced users and with extreme care and the Registry should always be exported or backed up before any changes are made.
1. Start the REGEDIT.EXE program.
2. Go to the key HKEY_CURRENT_USER\Software\Microsoft\Windows\Current Version\Explorer\RunMRU
3. A list of the programs that have been run from the Run command is shown.
4. Highlight the letter of the program you want to remove from the MRU list and press the DELETE button.
A word of caution is necessary here. Be careful not to delete the Default value or the MRUList value.
If you want to delete all the commands in the MRU list, then the process can be automated by creating and saving an empty MRU list in a Registry file and then merging this file with the Registry. Create a new file with Notepad or any other text editor and give it the name CleanMRU.reg. The extension reg signals the explorer that this file is a Registry file to be merged into the Registry. The following lines would completely clean the MRU list
Code Listing 3. Clean MRU command list Registry file
REGEDIT4
[HKEY_CURRENT_USER\Software\Microsoft\Windows\Current Version\Explorer\RunMRU]
"a"=""
"MRUList"="abcdefghijklmnopqrstuvwxyz"
"b"=""
"c"=""
"d"=""
"e"=""
"f"=""
"g"=""
"h"=""
"i"=""
"j"=""
"k"=""
"l"=""
"m"=""
"n"=""
"o"=""
"p"=""
"q"=""
"r"=""
"s"=""
"t"=""
"u"=""
"v"=""
"w"=""
"x"=""
"y"=""
"z"=""
Double click the file in Explorer to launch it. If everything completes successfully, you will get a message the contents of the file have been merged into the Registry. You need to restart Windows so that your changes can take effect.