Minecraft and other things not working correctly

[Steeled]

I recently started using a lot of mods and now everything has gone to hell. My Minecraft stopped working, so I deleted all the mods and .minecraft itself. About four days ago, I installed minecraft and technic pack and everything has been working splendid. I deleted all versions of Java on my computer, and installed Java 7 64-bit, which is linked on the home page of www.technicpack.net. I changed my enviromental variables (you know the "Path" one) to the correct location of Java. Everything has been good except two days ago none of my minecraft sounds were playing right, and in Tekkit the sounds worked fine but mAtmos sound mod (or whatever it's called) was not playing anything, even though I had heard it the first time I logged in to Tekkit. So to fix it I just decided to delete everything and start off fresh. Well, unfortunately, minecraft will not download at all. I downloaded the Minecraft.exe off minecraft.net, and after logging in, the download will not complete. It starts to download lwjgl.jar, and gets stuck at around 8%. I tried switching my versions of Java, and it didn't work. Windows Firewall is not enabled on my computer, Norton Internet Security is, so its not like it is blocked or anything. Just for some added and rather interesting info, Spoutcraft is having a hard time getting an internet connection also. TechnicLauncher works fine however. Everything else downloads and works on my computer just fine, but minecraft (and Spoutcraft) are not downloading. Spoutcraft gives me "download failed" and minecraft just doesn't download. I have had minecraft since 2010 and this has never, ever happened to me. I don't see how it could be my internet, as lately my internet has been very fast (speedtest.net and other websites clock my internet download speed at 40 MB/s upload 32 MB/s), and I have not messed with port forwarding or anything of the matter in months! This is very frustrating that I can't get minecraft to download. I tried forwarding port 80, and I did successfully but that didn't help at all. It has not been downloading for 2 days now, even after re-downloading the .exe and many computer restarts. Here is some extra info:

Java version: Java 7 64-bit, Version 4

Firewall controlled by: Norton Internet Security 2012 (have had Norton Internet Security since I got my computer, I don't think it is the problem)

ISP: Verizon FiOS

Computer build: Above awesome

Other added info: There is a light on my router (it's a picture of a globe) saying if it is getting an internet connection, it went red for an hour, so I turned it off. After turning it back on, it had a connection, but when friends tried to join my minecraft server, they couldn't join. My external ip had changed! I gave them the new one, all my forwarded ports still worked fine. My external ip has not changed in 2 years, so it was pretty shocking (I have restarted my router many times before). I don't see how this could affect ONLY minecraft and spoutcraft not downloading, but there you go, just in case. I really hope somebody out there knows what's wrong, as this has been going on for two days now and I have not been able to play minecraft.

[Steeled]

Hmmm well I disabled a different Anti-Virus program I had on my computer... AVG 2012. and for some odd reason it worked afterwards. I guess it was blocking it for some reason, even though I've had AVG for a couple months now. Oh and I tested it, the download worked 3 times over lol. I'm not closing the thread however, as this happened one time (I found a way to let the download through yesterday) but then it stopped working again.

[Torezu]

Hmmm well I disabled a different Anti-Virus program I had on my computer... AVG 2012. and for some odd reason it worked afterwards.

Yeah, this thread mentions that. Of course, it also mentions Norton...

[Steeled]

Of course, it's me who downloads the shittiest anti-virus programs. Although this did happen to a person I know about 7 months ago and after he disabled Avast it worked fine. AVG was free and Norton I got a discount on. *thumbs up*. Norton has saved my ass a couple times though, so I don't think it is that bad. I remember going over the COMMON PROBLEMS AND SOLUTIONS thread but I don't remember seeing that. Thanks for pointing that out. I guess I should try out Spoutcraft now.

[Torezu]

Avast! and Microsoft Security Essentials are also free, and both work quite well.

[Zero_Alkaiser]

Im having a simlar problem, though thanks to the advice here i have gotten almost all of it solved, im still having issues with the sound though, i changed my anti-virus and updated my java after i figured out how to do that, but my sound still isnt working, mod sounds still work but vanila doesnt.