To disable tooltips follow the steps given below.
1. Click on Start, click on Control Panel, click on Classic View, and click on Folder Options.
2. Click on the View tab, scroll down to the bottom, and uncheck Show pop-up description for folder and desktop items.
3. Click Apply, and then click OK.
4. You will no longer receive tooltips for folder and desktop items.
For more information follow the link. Tooltips and Infotips