MacBook Pro Cannot Connect to the Internet

Question

My MacBook pro was perfectly active and online, in my linksys router last night before I went to sleep. I left it active as I was downloading some files, they were going awfully slow, but I didnt pay attention and left up. When I woke up today, and tried to use my computer it seemed to be kind of slow and frozen, so I forcefully shut it down and then powered it on. Everything was normal, and my airport card connects to my network, as it is supposed to do. I try to load Safari, Mail and even Firefox, but nothing works. All my other programs seem fine. I started running Virex to see if it detects anything, but I dont know what is happening.
I have made sure that my network is working, since 3 of my roomates use the same internet from the same router, and they all have internet. Even my iPhone has internet. Everything is working except my MacBook pro.
So, I tried going to preferences and getting a renewed IP and DHCP server, like I do when the computer is lagging a little bit, it did not work either. I have reset again, by using normal reset setting on Finder. Still no Internet, I have no clue what do or why it's happening, this has never happened before, and I do not think is anything but my computer software.
I appreciate any help and suggestions. Thank you very much.

Answer 1

Yes, and when I open the Network Utility it shows a working IP address, and a 54Mb/s speed from the wireless router. It even shows the shared computers from my roomates. But when I try to access the internet it does not load anything on Safari or Firefox ( or any other internet application for that matter). It is completely unconnected. YET, As soon as I activate the AirPort card on the top right where I have my signal strength, it shows on the Network Utility information that there are 'packages' being sent and received, and I have NO programs open what so ever, I have closed everything except finder and network utility... Does this mean I am being hacked, or have some sort of Trojan or something in my computer? I ran an antivirus that my school provided, called Virex by McAfee, it came out clean except it says it cannot read one file.
I tried repairing my disk, and that did not work either. I did the Ram reset like you suggested, but that also did not work. I doubt it being a hardware error. I am going to try to connect it to an ethernet cable to see if that will work. Then I will let you know what happens with that, but that would still not be a solution since I need it wireless, cause the router is in another part of the house.
Thank you for your help, and I hope we can get this sorted out.