Slowdown after installing this week's patches

Yesterday I downloaded and installed successfuly the 8 updates from
Microsoft, including this one for IE7:
Cumulative Security Update for Internet Explorer 7 in Windows Vista (KB944533)
Installation date: ‎2/‎13/‎2008 10:48 PM

Installation status: Successful
Update type: Important

Security issues have been identified that could allow an attacker to
compromise a system running Internet Explorer and gain control over it. You
can help protect your system by installing this update from Microsoft. After
you install this item, you may have to restart your computer.

Since, when I access the Internet, it is 10 times slower than before the
updates.
I am a broadband user, the problem occurs regardless if there is nothing
else processing in my computer and even when accessing basic low-graphics
sites.

I found that after starting to get too slow, if I reboot the system, the
access is a little faster, not like it was before the updates.

I remember when IE7 was released under XP, it was slower until you disable
the Phishing feature. Currently, my system shows Internet|Protected Mode On.
Is this part of the problem?

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HP Pavilion Elite m9040n 2.4gh 3gb mem 640gb hard drive, dvd lightscribe
technology burner, Vista Home Premium, Office 2007