Why the buttons don't show up?

This issue is caused by the screen resolution and DPI of the computer. Just adjust the screen resolution to 1024 * 768 or higher and DPI to a smaller size to have a try.

For Win 7 or Vista:

1. Go through the following link to see how to adjust the screen resolution: http://windows.microsoft.com/en-US/windows7/Change-your-screen-resolution

2. For DPI, uncheck the Use Windows XP Styple DPI Scaling option, which is selected by default. You can go to Start > All Programs > Control Panel > Display > Set Custom Text Size (DPI), and find the  Use Windows XP Style DPI Scaling option.

For Win XP:

1. Right click on a blank space on desktop and choose Properties.
2. Choose Settings > Screen Resolution and adjust it to 1024 * 768 or higher. 
3. Go to Setting > Advanced > DPI settings and change DPI from 120 to 96 by clicking the arrow.