Help? :[

I really hope I’m posting this in the right section! If not, I’m SO sorry!
I’ve been having a few problems using my dads PC since my laptop has been acting retarded.
My first problem, I cant connect to itunes. It says I’m not connected to the internet, etc. I was wondering why this is, because this problem just randomly came about last week out of nowhere. It was fine like day before, and then it suddenly stopped working.
My second problem, I’m starting to think the two are related somewhat, I cant seem to connect to any online games. I play Maple story & Audition, and around the same time my iTunes started saying “I wasn’t connected to the internet”, Maple story & Audition started doing that too. When I try to load maple story, theres this page where they have all the updates and stuff, and instead of seeing all of the pictures and what not, it just says navigation to the webpage was cancelled, and then when I click the play button, gamegaurd works and everything but it says that maple story cannot connect to the login server. Same with audition, everythings fine, the game opens, but when I get to the logging in part, it says it cant connect to the server.
My third problem, I cant connect to the internet using IE7. Firefox is fine, but IE7 says that I’m not connected. This started yesterday.
I tried system restore, but I think that was useless because it creates a new restore point every time you install/uninstall something, and I was getting rid of the crap on here so all of the restore points were from the same day, therefore it didn’t work :[.
And my last problem, my brother deleted my hosts file in an attempt to help me. It didn’t work (obviously), and I was just wondering if this was important, and how could I get it back.
As for everything else I said, I know it’s not my internet connection. I have a very good DSL connection, and other than those 3 things everything works fine. I was googling these issues earlier, and as much as I think IE is to blame, I cant get rid of it because iI’m using vista.
So I was just wondering what I can do to fix these? I followed the instructions on nexons website for the errors I was experiencing, and it didn’t work. I feel as if I’m out of options, and wanted to know what more I can do.
I don’t think I have any viruses, I disabled my firewall before I ran the programs, Closed anything that would interfere with how they run, disabled my av, etc, and nothing.
Any help would be appreciated!
-Megan

 

Try this: go to the Control Panel and open Internet Options. Click the Advanced tab. I'm not using Vista, so this is from memory, so bear with me here There should be two buttons, both say something like "Reset settings" or something. Click one, agree to all it's warnings, let it do it's thing, then click the other and do the same thing; agree to the "do you really want to do this" type of stuff and let it do it's thing. When it's done (shouldn't take but a few seconds) close the Internet Options window, click the Start circle-thingy, and in the Search/Run bar, type http://www.majorgeeks.com and press Enter. With any luck, the MG front page will open, and there will be much joy and glory. You can then go back to Internet Options and set your home page to whatever you want. I know this sounds pretty freekin' easy, but it's worked for me on many Vista systems where IE doesn't work, but Firefox does....