Excel uses Windows colors for several of its elements. You can change these colors for Excel by changing the Windows colors. 

1. Click Start, point to Settings, and then click Control Panel. 
2. Double-click the Display icon in Control Panel, click the Appearance tab, and click the element you want to change in the Item box. 
3. You can then click the color and font color you want for each item: 
   

3D Objects:Sets the background color of the Excel row numbers and column letters, and also the inactive sheet tabs. The font color sets the color of the row numbers and column letters, and the text on inactive sheet tabs.

Selected Items:Sets the color of the highlighting Excel uses to indicate which cells are selected. This highlighting is a muted version of the color you specify.

ToolTip:Sets the default background color for worksheet comments. The font color sets the default color for comment text. You can also change the background and font colors for individual comments. For more information about changing comment colors, type format comments in the Office Assistant or on the Answer Wizard tab in the Excel Help window, click Search, and then click the topic "Change the appearance of a comment."

Window:Sets the sheet background color. The font color sets the default color for data you enter in cells, and the color of the text on the active sheet tab. You can also change font and background colors for individual cells or an entire sheet. For more information about changing colors of cells and worksheets, type format worksheets in the Office Assistant or on the Answer Wizard tab in the Excel Help window, and then click Search.

Changing the gridline color: You can set this color in Excel. On the Tools menu, click Options, click the View tab, and, under Window options, click the color you want in the Color list.