I don't believe the pop up blocker in the Google Toolbar will slow down your PC but if you don't want to use it you can simply turn it off and still continue to use the Google Toolbar if you like. Since I use My IE2 and it has a built in pop up blocker I have turned off the pop off blocker in the Google Toolbar since I don't need it.
What is probably slowing your Computer the most is adware/malware/and spyware.
Download / Install / Update / and Run .
Then:
Download and run:
If you're still having problems:
Download and install . Now Run it and post a copy of the Log File here.