I had the same problem.
Comcast kept telling me it's on my end.
They must have a 5 ft high stack of complaints from me by now.
however, a sharp Comcast inside tech identified the problem as being in the outside wires.
He made an appointment for a comcast outside tech and lo and behold, they found 2 things wrong.
1. a squirrel had partially chewed through the wire.
2. a connection\coupling was encased. The encasement had filled with water. ( Makes Sense that the service was spotty, when you consider the continuous freeze & thaw)
They replaced the chewed wiring, sealed the encasement and my speed is now screaming.
You have to keep hammering ‘em to get a decent outside guy out there. preferably a comcast guy not a sub contractor
Good luck
Macbots in 3...2...1...
Are you logged in?
That would have fixed it if done properly.
What did you "reload" onto your hard drive after formatting it? An image? A clone copy or just your personal data?
If it was one of the former two, you've brought over whatever virus (virii?) or spywarez that were the problem in the first place.
"Nasty little Spywaeses. Always trying to get to The Precious."