That's simply a windows theme issue, I didn't use Vista for a long time because of how shite it was so I can't really remember how to change the theme.
Here's something off a random site:
• go to your desktop. In any blank area, right click.
• scroll down to “personalize†and click.
• a dialogue box will come up that says: “Personalize appearance and sounds.†Right below it are seven headers. Choose “theme†which is the sixth item, or second to the last item.
• a dialog box appears with the title “theme settings.â€ÂÂ
• under “themeâ€ÂÂ, you have a small box with a drop down menu. If you click on the arrow, Windows Vista gives you four choices: current theme, Windows Vista, Windows Classic and browse (the browse option allows you to get a theme that you saved in a specific folder. When you choose browse, Vista automatically takes you to your downloads folder where you saved the theme).
• when you click on any of the four choices, you get a preview of the theme. Choose one by clicking “apply†or “OKâ€ÂÂ. If you don’t like any of what you see and decide to stick to what you have, simply click “cancel†or close the dialog box.
It's safe to assume your PC has set the theme to "Windows Classic", you will want to change it back to "Windows Vista" theme setting.