PR dropped 1 point with new Google Toolbar or Santy Worm?

[Frank_Rizzo]

Yesterday I installed the latest version of Google Toolbar (had been using older one for a year).

Today, I notice that the website has dropped from PR5 to 4. Surely, the change in toolbar has not done this?

Nothing much changed with the website. There are the same number of inbound links as before, and the site still ranks #1 for top keywords.

If it's not the new toolbar then could the PR drop be due to the Santy worm? The site has about 18,000 messageboard pages indexed in google. Is google penalising because so many infected PC's are seeing the sites name used as worm bait?