Having a sudden slow start up with Vista

[Castout]

My experience with Vista has been a thrill it's fast enough for me though I do maintain my PC with registry cleaner from time to time and use a reliable firewall and AV.

But since yesterday every time I boot up the PC it would start normally until I sign in to my account and then all start up system tray would load perfectly but the taskbar would be frozen and I couldn't start anything from my desktop shortcut. The network icon would sometimes appear to load last and after about a minute or a minute and a half only then I regained control of my PC.

I ran two different registry cleaner and all reported my system registry to be clean.

I checked the start up item and found no suspicious entry.
I even disabled the Windows defender of fear it might conflict with my COMODO.

But all to no avail.

Checked COMODO installation through their in built diagnostics and it didn't report any problem.

Disabling sidebar at start up didn't help either.

Ran HijackThis and found no suspicion entry too

Ran msconfig and set to boot with maximum memory besides booting with all cores.

Checked BIOS and turned off displaying full logo(couldn't find anything more useful to help with booting)

The only thing I haven't tried is reinstalling COMODO but I'm so reluctant to do this.

Does anyone have any idea?
I thought I post here as the internet seems to work wonder for me. I posted about the women who was an annoying nuisance at my church and she was no longer there in the weekend . Maybe she read my post or found a new religion such as self worship or whatever(about time) LOL