Blurry graphics in Win XP / IE 6?

[Jaimer]

A designer and I have created a site that looks fine on every pc-OS-browser combination except for Windows XP and IE 6. Slanted lines appear jagged, and small text is basically illegible.

We have tried:
- The default screen resolution was 1440x1050, but lowering that value did not improve the quality.
- We have tried a lower compression.
- We have tried Smooth Anti-Alias and Crisp Anti-Alias.
- The graphics are vector-based.

Any ideas?

[Jaimer]

Could the issue be a browser and/or monitor setting? The site looks fine in IE 6-Win 98 and Win 2000-Netscape, Win 2000-IE 5.5.