Chrome Login Problems
I had a problem for a while when using Chrome on XP, where I could not log into various sites at all -- it worked from IE7 but not from Chrome.
After a while, I got annoyed and started looking for a solution. It turned out to be an easy one: Chrome was configured to accept no cookies.
Go to Wrench > Options > Under the Hood, then look for the Cookie Settings. It should say "Allow all cookies". If it says "Block all cookies", then you'll be prevented from logging in.