Este é um problema conhecido
XP contains a known bug that causes the CPU usage to spike to 100 percent when you access the context menu under certain configurations. This bug causes file-copy operations to halt, network connections to slow, and streaming media (e.g., audio, video) to become distorted.
To work around this bug, you need to disable the GUI's transition effects by performing the following steps:Start the Control Panel Display applet. Select the Appearance tab. Click Effects, then clear the "Use the following transition effect for menus and tooltips" check box. Click OK to close all dialog boxes.