Hi!! You should tell us more about your computer and the kinds of programs and things you run. When did this problem start? What were you doing ? Did you install a new driver or program ? Is the problem off and on, or constant? Have you changed to a different screen resolution? If so, set it back to standard or recommended resolution. See if that helps.... There can be many things causing the problem. Conflicts with other programs, video card going bad, screen going bad, too much graphic acceleration. Is the whole screen fuzzy ? Or just certain parts ? Sometimes if just text is affected it could be a problem with DPI.
Can you post a screen shot, or a snapshot of a portion showing, at least, some text on you screen?
We can narrow it down then. If the snapshot looks good on these pages, then there is nothing wrong with your card or the Vista setup, which means you have a monitor hardware fault.