First off, just to avoid the sake of repeating myself I'd advise that you read up on the forum post posted below for any background information. I'll fill you in on the new main problem etc. but basically this post explains what issues the problem is creating.
"Consistent problem with my Xbox 360 Slim dashboard": http://forums.xbox.com/xbox_support/xbox_360_support/f/7/t/2043760.aspx
Now, onto business. To put it the short way, the Internet on my Xbox 360 Slim isn't working properly. To put it the more detailed way, the Internet on my Xbox 360 Slim isn't working properly, but the Internet connection (wired or wireless) on every other device in the house works fine, with very minimal lag or overall connection issues whatsoever. As a result this is affecting, of course, my online connection to pretty much anything and everything. Online games, online apps, party/game chat... even my Dashboard is having a hard time loading due to this unstable connection. Quite frankly I don't understand why the Internet on the Xbox just suddenly stops working properly, because that's pretty much what happened. One day it was working fine, and the next day it just started slugging around without any warning. Only problem is I can't see the trail the slug is leaving behind, so I have no idea as to why this is happening or how to fix it.
I've read up online in several places and tried a multitude of things. I've cleared my system cache at least 10 times, removed 3/4 of old friends that I don't really do much with anymore, removed some DLC games I'd gotten off of the XBL Store, and I've even switched the Ethernet cables. None of which have made any positive impact whatsoever. And top of that, it seems to be getting worse. I can barely even join parties anymore as it just keeps lagging me out, and I often get random disconnects when I least expect them.
...should I go on? I think I've made my point, haha. Ultimately I've tried a multitude of things and the problem seems to just be getting worse. And the annoying part is is that sometimes it works fine, and then it stops, then it sort of works... It's like a compass that can't figure out which way is North.
There is one thing I did notice, however, only just last night. The console itself seems to get rather hot on the fan section, but not hot enough for it to overheat. In saying that, however, the console has frozen a couple of times ever since it started being sluggish, but that's mainly been from me trying to download updates or profiles and cancelling them, or trying to multitask the console before it's even finished doing one thing. I figured that for those reasons the Xbox was just freezing mainly because of the unstable Internet connection, so downloading updates would be an issue to start with as it would start it, then cancel due to a disconnect, then try to start it again bla bla bla... But considering the console is considerably hot it might be a possible symptom, even though when the console does work it works with minimal issues whatsoever (apart from the Internet connection, of course...). I did take it apart last night to clean out the dust it catches (don't worry, the warranty was already voided and I'm not that eager for a professional fix...) in case that might be why it was heating up, but it's still getting quite hot today. I thought fans were supposed to cool things, not heat them. :l
But anyway. that's about what's going on here, and I'm desperate for a solution as it's racking my brain as to why the console isn't working properly, but everything else is. I should re-note that it is a pre-owned console, but I've owned it for about 3 years now and had no issues like this up until now, so I dunno. Sorry for the long-vented post, but I figure you'll need all the info you can get to unlock this dark mystery... ()._.)