On my parents laptop (which I never use unless I have to) I can't log in to certain websites like reddit, digg, shuttercal, and a few others. There's no error message, I just end up getting REDIRECTED to the homepage over and over again WITHOUT being logged in. I've tried using Firefox, IE, and Chrome, but it makes no difference. I cleared the cache and deleted all the cookies again, with no difference. Restarting the computer does nothing, and it was recently defragged. What REALLY stumps me is that I am able to log into other websites like Gmail, my bank account, and Livejournal.

The computer is pretty old-ish, I think my parents bought it in 2002, it's an HP laptop that runs Windows XP. Anyone have any ideas as to what is going on and if/how I can fix it?

EDIT: Also, I've tried accessing the sites I can't log into through a proxy, but that doesn't work either. It could be parental controls. 

It's not your computer, we won't help you circumvent it.It's not parental controls. First of all, I'm 19. Second of all, the pages themselves aren't BLOCKED, it's just when I try to log in that I get redirected over and over again to the main page. There's no 'Enter password to access site' window that pops up or 'Page X blocked for Reason Y' page, and I don't see why parental controls would block something like Reddit or Shuttercal (a photo sharing site). ask your parents if they put any security software that blocks certain sites or whether they have enabled anything that may be blocking you from going to sites.. If there's no such thing, and you're allowed to use the computer, then we'll try to help fix that problem.

With parental control software, one can block websites so that little kids can't accidentally go there. And so if Shuttercal or Reddit is blocked that way, then yeah it could. But I don't know about the parental controls coming with vista though.
No, there are no parental controls/security software, and I have permission to use this computer. Can you find anti-virus websites?What firewall do you have?Okay just as an update: I figured out what was wrong. My mom installed CA Security Center on the computer which is an unbelievably *censored* program. I disabled the firewall, and that solved pretty much every problem I was having with the internet on this computer. Quote

My mom installed CA Security Center on the computer which is an unbelievably *censored* program

I disabled the firewall, and that solved pretty much every problem I was having with the internet on this computer.