Internet Explorer works very slow

My situation is as follows;

I have IE 7.0.5713. I am running a internet connection between my systems
and a router, which is a D Link 1310 and a broadband connection with a cable
modem. There are two other systems on my network, one is running Vista and
the other is running XP. I am running XP Pro with SP3. The other two PC's are
running wireless connections and do not seem to have issues with slow
connectivity and slow performance with IE 7.

I have tried running software to remove adware and tracking cookies from my
system. The software I am, and have used are; Ad-Aware 2008, AVG Anti-virus
and Windows Malicious software tool. The success of these software tools are
sporadic, Sometimes after running Ad-Aware 2008 and then restarting my
system, I get excellent response via IE7. However, depending on the website,
the good performance of IE7 may not last until, the next time I start up my
system. I notice that sometimes, tracking cookies seem to appear and I have
to run through the process of using Ad-Aware 2008, AVG Anti-virus and Windows
Malicious software tool to get the performance back to IE7.

I even have to sometimes turn off my cable modem and my router and restart
them to get the performance back.

I also have a sporadic problem of the Internet Connection icon appearing in
the taskbar. Sometimes it is there and sometimes is not. I notice that when
it is not there, the performance of IE7 suffers because of it.

At this writing, I have excellent performance. I have also tried turning off
Windows XP firewall because of the firewall capabilities of my router; think
that maybe the dual firewall (software and hardware) may have a contribution
to the slow performance. This has not yielded a benefit. I currently have
removed my PC from behind the router firewall and turned back on the Windows
firewall, and it seems to have helped.

I have also tried to use Firefox and run into the same issues. I have
deleted Firefox and I noticed a resulting problem from this deletion is; my
“Quick Launch� tool bar (just to the left of the “Start� button, has
disappeared, even when I right click on the taskbar and go to “Toolbars� and
make sure that the menu choice is checked for “Quick Launch� is checked, it
does not reappear.

However all of these trails seem to be that I am holding together my IE7
performance with spit and a prayer! Can anyone help to get my IE7 to be more
dependable and predictable? Also can anyone advise me on getting back my
“Quick Launch� toolbar on the taskbar?