Windows 7 Jump list history feature  

You can prevent it from :

Now if you want to permanantly disable Search MRU list,

1. Click start and in the search area type gpedit.msc

2. Now the group policy editor will open. In it go to User Configuration > Administrative Templates>Windows Components>Windows Explorer

3. In the settings panel under Windows Explorer look for Turn off display of recent search entries in the Windows Explorer search box

4. Right click it and select edit

Use not configured or disabled to keep search history enabled.

Use Enable to disable the search history


Courtesy : http://dotnetwizard.net/h...