Sorry for the delay, coz I got stuck up...
Firstly, I tried your basic resolution. The system started within 1 min! However, as I was trying to report that good news, I found the internet being disabled...
Then, I tried to enable most startup items, so that it matches the original setting. The system still started up quickly, but the internet was again unavailable.
So, I had to enable some of the services. It turns out that enabling all services related to Symantec can work. On top of that, the system started within 3 mins. Not fast enough, but sounds better.
The only issue I am concerned is that the post logon black screen still appears, and the Windows tune is still played during the black display. Shall I do something to it? Coz I read from various resources that there could be a problem with those black screens. Also, the "symantec disabled" note still shows up.