I cannot change my desktop background, it is locked on yellow and the browse button is grayed out - Help!!!!!!!

1. Right-click My Computer and then click Properties.

2. On the Advanced tab, under Performance, click Settings.

To select all of the check boxes, click Best Appearance. To clear all of the check boxes, click Best Performance. If you select Restore Defaults, several check boxes are selected. The default selections are determined by your computer's capabilities.