IE says that it cannot display the webpage...

Well...if your connection works then explorer should be able to, however maybe your DNS server is down, in which case you should change it. Try a couple different URL's to see that it is your problem and not the websites problem.
-If you don't know how to change DNS or what it i, then say so and i'll tell you

Alright so here is what you do:
-Open up Control Panel
-Find "Network Connections"
-Now, you are on wireless right? If you are, select whatever option you have that has the word wireless in it...it can be called "Wireless network connection" or some other names very similar. Local area connection is if you have wired internet so dont touch that. Then once you find it, RIGHT click and select Properties. Then once in properties it will say "Internet Protocal (TCP/IP)"...if your selection also has "Internet Protocol TCP/IP Version 6 or version 4, make sure to select 4 because version 6 doesn't exist yet
-Left click on "Internet Protocal (TCP/IP)" to highlight it and then below it click properties.
-Once there you will have the option on the bottom called "Use the following DNS server addresses", make sure that is selected instead of "Obtain DNS server address automatically".
-Put in the ip address of a DNS server. There are tons of free fast dns servers online. I recommend Open DNS, its address is
Preferred DNS Server: 208.67.220.220
Alternate DNS Server: 208.67.222.222

-Any questions ask
-Good Luck

true that, should of actually told him to do that first.