Operating System Windows XP many interface with menus that slide into view, shadows effect that create three-dimensional effects, and rounded corners that soften the appearance of windows. For an older computer, these effects make slow down it’s performance. For example, dialog boxes and menus might not open smoothly. To improve and make faster the performance of your computer, you can disable some or all visual effects.
Step 1 : Click Start –> right-click My Computer –>Click Properties.
Step 3 : Performance Options –> Visual Effects tab –> Custom option.
Step 4 : uncheck for the visual effects to disable.
Step 5 : Click OK –> back to System Properties dialog box. Click OK