Limited or no connectivity (Dell, Windows 7)

I just moved to a college for grad school and bought a new laptop. Dell Inspiron with Windows 7. I know how to use a computer but am not very well versed in 'tech' stuff...so please bear with me and if you need more info just tell me. I also will need detailed ts instructions... =D. I had no issues ever connecting to my wireless network (via wireless router) at home.

I moved into my apartment at school which is a university apt and could not connect to the university's wireless network. While walking on campus they had IT people (students) ready to help any incoming students get their appliances connected. They connected my laptop and my iPhone. My iPhone has not had any problems since they connected it...my computer on the other hand has had shoty connection every since.

When they initially connected me they put on a Cisco NAC Agent onto my computer (that's what the university uses). It worked for the rest of the day and then I turned off my computer when I went to sleep. The next day I could not connect. I took it back to IT and they removed my McAfee security suite which came free for 30 days with the computer and installed Microsoft Security Essentials. I got connected fine. I even turned off my computer and restarted it and connected again to make sure it worked. But this Cisco NAC thing comes up and has us sign in with our university username and password.

Now.. the option to start the connection automatically is not a check box on my wireless network...so I am connecting manually. I've had an array of issues. First being that I will be browsing fine but when I try to go to another page it says "Internet Explorer Cannot Display the Webpage". Trying to diagnose the connection error doesn't help...it just tells me to reset my access point (router?) which I can't do b/c I don't have a router in my apartment. Second issue is when I am not connected and try to manually connect...the Cisco Agent doesn't even come up -- this results in me getting 'connected' with a good signal but with 'no' or 'limited internet connectivity'. I've also noticed a couple times that if I am connected and browsing and go to another pg that won't display, when I look at the wireless network down in the right corner of my computer screen, it no longer lists the name of the university's wireless network that I connected to but says "unknown wireless network" and 'limited/no connectivity'.

I am going to take it back to IT and explain that I can't continue to have this issue but is there something that sounds like you know what's going on? Is it some setting that's getting screwed up or my IP address going bad or something....I need help =/

.....Oh, forgot to mention. I was on the internet browsing about 1/2hr ago and it turned to 'unknown' and 'limited connectivity' again. I turned the computer off for about 1/2hr and turned it back on to try and when I manually connected, the Cisco came up and I am obviously on the internet right now....no telling for how long though.