You’ve gotten a lot of good advice on this thread. One other thing to check ... does your computer have multiple modes of accessing the internet turned on? I’ve seen devices that are using WiFi, Phone Cards and a wired connection and they are all battling each other for dominance. Turn off the extraneous modes and it boots a whole lot faster.
To link two bits of advice you’ve gotten so far — if you do have more than one mode of internet connection trying to connect at the same time, remember if you do disable your firewall or antivirus, to be sure you’re not accidentally still connected to the web.
Especially if your “other” connection isn’t securely behind a router.
There is one other possible course of action - but you really need to be ready to throw caution to the wind if you decide to go this route. You could use the situation as an excuse to install Linux on your machine.
Thing is, if you don’t like it, that can be a big step to try to get back from.
Good luck to you.