Connection Timed Out - Selection of Websites

[Reapt]

Ok, so we can pretty much narrow it down too a couple of things here. First let's see if it's still something to do with the ISP.
Open the command prompt and do one last command for me.
tracert dropbox.com

This will do the same thing as ping but it pings every location between you and the destination. It essentially traces the exact route you take.
So watch it and see where it times out at. If it's anything but the first(possibly second depending on your network) it's not on your end because the first ping is your router, and every other ping after that is your local ISP - ISP DNS - destination router - destination (something similar to this)

I am at my university working with my project group. The university has a wifi network and from this network I can access all websites without problem. So my guess now is I will have some dirty work with my ISP's router. I have had some bad experiences in the past working with router ports and all that crazy network configuration. Any tips on how to start?

I didn't even see this post. I would login into the router and reset it. To do this when you are at home connected to it. open up a broswer and enter this as the url:
192.168.1.1
If that doesant work try:
192.168.1.2
192.168.0.1
One of those will open up essentially the gui in your router. Just reset it, then reboot it. Let me know if that works.

still recommend the tracert command as well. It might not be a problem with your isp's router it could be a broken link in between(still a problem on the ISP)

If you are wireless you may need to hardline into the router for this(maybe) and if you reset it please dont forget to turn back on the wireless encryption(WPA always)

 

[JDX45]

Came home, booted pc and suddenly for whatever reason dropbox.com and di.fm are working again, which means problem fixed! And I didnt have to do anything! Im so happy I really need dropbox for university projects.
Thank you so much for your help! This was my first thread on this forum and your answers alone made it worth registering on here
One last request: if you have any links that made a big difference to your knowledge base related to linux and network management, that helped you learn a lot and easily, I would appreciate if you could paste them here.

P.S. - sorry for the trouble

Once again, thank you guys! You're awesome!

 

[Reapt]

Well that's good man! Sounds like something on your ISPs end or your DNS catch. Regardless I would still want to know what it is but that's just me lol.

I learned what I know with my degree in computer science, passion for wanting to learn(I have about 60+ books on programming, networking, etc. I'll admit I haven't finished like 1/3 of them but I've read most of the material in them), And of course my 6 month experience at a network admin assistant, web developer, and my currently ongoing experience as an IT security/operator for my current job.

I would recommend cert books. I currently have the all in one A+ cert book, the all in one network+ cert book, the Linux cert book, and various programming ones. MySQL, PHP, lua, HTML, C#, Java, etc.

Here is some laying around my house. That i would recommend:
http://www.amazon.com/CompTIA-Network-Certification-Edition-N10-005/dp/0071789227
http://www.amazon.com/CompTIA-Certification-Edition-220-801-220-802/dp/007179512X
http://www.amazon.com/PHP-MySQL-Mis...1-1&keywords=php+and+mysql+the+missing+manual
http://www.amazon.com/JavaScript-jQ...ords=javascript+and+jquery+the+missing+manual
http://www.amazon.com/HTML-CSS-Desi...8&qid=1398607486&sr=1-1&keywords=html+and+CSS
http://www.amazon.com/Programming-u...oks&ie=UTF8&qid=1398607499&sr=1-5&keywords=C#

 

[JDX45]

Thank you very much I am studying informatics and computer engineering in Lisbon, Portugal (kind of the equivalent to CS) and I have some catch up to do concerning linux and network configuring.

Cheers mate