Vista problems with web site User ID/passwords

[adakim]

I just got Vista Home Premium with a new laptop and am having problems with User ID/passwords on some (but not all) web sites. I can log into (and save User ID) on some web sites with no problems. On some web sites I can log in successfully only if I do NOT save (leave "save password" box unchecked) password. If I try to save password, Vista just clears the User ID and password and ignores log in. For some web sites (such as Youtube), Vista will not recognize User ID and password and let me log in. It just clears the User ID/password fields. I have another PC with Windows XP Professional which does not have these problems (I verified that all User IDs/passwords are still valid). On the Vista laptop, I've tried lowering security levels, enabling cookies, etc. but nothing seems to work. Any advice would be appreciated. Thanks!