DL65,
thank you for your suggestions. I have downloaded, installed and run Ewido Security (as well as the online scanner beta), CWShedder, Stinger and CCleaner. This morning I updated every single one and ran them again. None of them seems to find an infection. However, G DATA anti-worm tells me that it "looks like" my host has been hijacked and it does provide me with a report, which, unfortunately, I can't understand. What I have noticed, though, is that all addresses end with #SpySweeperCASS, and since I have Webroot Spysweeeper as resident, I'm not sure how this can indicate hijacking.
I continue to be unable to protect against the several instances of BlockCheckers, Clickzs, CoolWebSearch, mirar and Z-Quest that my (newly downloaded version of) Spyblaster indicates are "unprotected".
I was hoping that you might provide other ideas.
Thank you.
I'm wishing you well.