AOL, and some other nasty sticky programs leave registry codes behind, and the only way I know how to rid of this is doing a reformat, and reinstall of windows.  Lots of work, saving the stuff you want to keep on a cdrw or dvd, than wiping the system clean.  Someone else may have another idea, but the reformat works for me when I had AOL, McAfee. 

 

AOL is the most highly distributed virus in the world.

 

Good luck with that, but a reformat is the only way I know as well.

Just do this after you uninstall the AOL suite, Go to start, run, type regedit. Then when it's up go up to the top and click edit. Now go down through that drop down and select find. Type in AOL on the top there. Start the find. Once it stops on the first AOL value, right click and delete it. Then hit F3 and it will go the next value for AOL. Do the same and delete it. Keep doing this over and over until it says registry search is done. But be aware to hit the F3 first to find the next value. If you hit delet twice you could end up deleting the next value and it probably won't be directly the next AOL value. Recap. Find, AOL, delete, F3. AOL, delete, F3.

Or you could just uninstall AOL the usual way. Reboot. Run a Registry Cleaner and voila.
As to it slowing down your computer...not likely. The only thing that can slow down your computer from AOL is a running process.