My Acer Aspire 5315

Hello,

My Acer Laptop Aspire 5315 connects to the internet but will only let me on a few sites, it was fine last night and has only started playing up today. I haven't changed anything and I've tried stuff on other websites but they haven't worked... I'm not a computer whiz but nothing seems to fix the problem, I've tried starting it in Safe Mode and that didn't work either all I know is that I use windows vista and I have a wireless router which also connects to my house phones and I use Windows Internet Explorer. oh and it lets me sign in to msn and I can access my e-mails and google but thats about it. please help as I need to use my laptop daily.