For IE 7, and possibly 8, 9 - you might consider --
click on Tools, select Internet Options, click on Advanced -- scrowl down till you see Browsing.
"enable third party browser extensions" and unclick. Will release on next restart. However - BE Warned - you may lose your third party toolbars, ex. google toolbar.
See if that speeds you up a little, worked on my daughter's IE 7. (you can always go back and reclick) Suggestion only, don't kill the messenger. Maybe someone else will chime in.
Additionally, if you do move from IE to firefox or Chrome, you will lose your "favorites" list (also known as bookmarks). So, if you have a packed "favorites" list (like me) be sure to write them all down before you do the switch. Switched my son's computer to Chrome and have to say, it is amazing. Much faster in our rural area. Chrome does have issues with privacy, so if you do pursue, immediately head to options and reconfigure privacy options to suit you.
Good luck my friends, welcoming any feedback.