How to increase or decrease the width of start button?

Follow these steps: 

Step 1: Goto start>>run and type regedit
Step 2: Now navigate to following location

HKEY_CURRENT_USER>>Control Panel>>Desktop>>WindowMetrics

Step 3: Now click on WindowMetrics and on its right side in empty space right click and selectNew > String Value

 Step 4: Now give it name as MinWidth

 Step 5: Now Double click on MinWidth and give the value as you wish(Enter Number ie.36,75..)

 Now at last restart your computer to see effect. Effect will be seen after restarting computer.....Enjoy