I think your website needs a colored scrollbar. Why is the main content written in Times New Roman? It would look much better in a font like Verdana, Arial or Tahoma. I hate the fact that the links (besides the one's in the navigation) are blue in color with underlines. I would change the color of the links to match the rest of the writing's color (which is black). Furthermore, I would get rid of those underlines on the links. I think the navigation on the left looks alright- it's just the scrollbars, the font of the writing (besides the one used in the navigation), alongside the underlines and blue color created on links that need to be changed. A few changes would drastically improve the quality of your client's site.
Edit: After taking a second look, I agree with the navigation idea. A different font color when the mouse is taken over the text would look neat.