I've been told a couple of people are being redirected to odd pages when they try to log on. I've checked the page code and the vBulletin site and there's no reports of problems. I can log in no problem using two different browsers -- Safari and Firefox -- but am on a Mac which generally is not affected by this type of problem (because these things are almost all written for Windows).
It sounds to me like there's a virus, some spyware, or malicious code generally that people have ended up with installed on their PCs that is trying to redirect them.
I'd do a couple of free online scans here:
http://www.kaspersky.com/virusscanner
http://www.housecall.trendmicro.com/
http://virusscan.jotti.org/
and see if anything comes up.
It sounds to me like there's a virus, some spyware, or malicious code generally that people have ended up with installed on their PCs that is trying to redirect them.
I'd do a couple of free online scans here:
http://www.kaspersky.com/virusscanner
http://www.housecall.trendmicro.com/
http://virusscan.jotti.org/
and see if anything comes up.