Weird problem with certain web pages being unavailable

[shmokes]

Hey . . . My friend's having a weird problem with his computer and it's got me stumped.  His internet is working, for the most part, but a few websites don't work.  They give him a Page Cannot Be Displayed error, as though he has no internet connection.  Here's what I've checked so far (albeit all over the phone):

His computer connects to a wireless access point.  IP Address and DNS server addresses are all handled via his router's DHCP server.  The other computer in the house, also grabbing DHCP server and IP address automatically can connect to these pages fine, so I know that the pages are not being blocked on the router or at the ISP. 

He gets the same problem regardless of whether he tries to visit the pages with Internet Explorer or Firefox so I know it's not a browser problem, though I cleared his cache and cookies in both browsers just in case and it didn't help.

Checked his hosts file and the only entry is 127.0.0.1 so nothing's out of whack there.

Again, the vast majority of web pages are fine.  It's just a select few, such as Hotmail and his bank's website.  He can get to the Hotmail website, but once he puts in his username and password it just gives him a Page Cannot Be Displayed.  He can log in fine on the other computer that also connects to the same access point, so I know it's not a problem with his Hotmail account.

Any ideas?

[saint]

Local firewall on the computer? That'd be the next avenue I investigated.

[clanggedin]

I've seen this happen before too on Hotmail.com

Check Windows Firewall. Sometimes it blocks decides to block pages. It may have to do with sercure web pages since it is blocking Hotmail and his banking webpage.

[CheffoJeffo]

Do a traceroute to the sites you are having trouble with ... every now and again I have customers experience problems like this and it is almost always a flapping router somewhere en route.

Cheers.