To change (increase or decrease) the number of recent items displayed in Windows 7 Jump List, please try  the following methods:

 

Method 1:

 

1. Right click on Start button.

2. Select Properties.

3. Switch to Start Menu tab and click Customize button.

4. Under the “Start menu size” section at the bottom of the “Customize Start Menu” dialog, set a new value for Number of recent items to display in Jump Lists option.

 

More information:

Customize the Start Menu Options in Windows 7 

 

Method 2:

 

Reduce or Disable Frequent Items of Windows Explorer Jump List in Windows 7

--------------------------------------------------------

Before modify the registry keys, please take a backup of the key. For more information about how to back up and restore the registry, please click the following link to view the article:

Back up the registry 

 

1. Type regedit in RUN or Start menu Search box and press Enter to open the Registry Editor.

 

2. Now go to following key:

 

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced 

 

3. In the right-pane, locate Start_JumpListItems (a 32-bit DWORD value) and double click it to edit.

 

4. Example of possible value for Start_JumpListItems value:

 

1)      To display maximum of 15 frequent items, set Start_JumpListItems to F or 15 (if Decimal Base is selected).

2)      To display only 1 frequent item, set Start_JumpListItems to 1 (valid for both Hexadecimal and Decimal Base).

3)      To totally disable Frequent item in Windows Explorer Jump List, set Start_JumpListItems to 0