Multiple Errors?

1---I have just WAYYYYY to many pop-ups about 6-8 an hour, even on idle computer.
2---It is so slow. When minimizing a page, I watch it close from the top of the screen to the bottom and that takes 15 seconds, and sometimes my icons are missing when it finally fully minimizes.
3---After booting up it takes me a good 5 minutes before the mouse's "time-sand" icon to dissappear, therefore not letting me do anything with the computer right away.
4--Sometimes when using websites like "google" or "yahoo" from internet explorer, there is a big delay from when I type in the words, and those words to appear on the screen.
5---Streaming movies from websites are rarely synchronized with the sound and the picture on the screen, something that none of my friends have.
6--I revently purchased an external hard drive, and ever since doing that a message comes up within seconds of turning on my computer that reads something along the lines of "Unkown Devise, hit any key" then it boots up normally (note: The slowness of the computer has happened way before the external harddrive, and purchased it with hopes that would cure some of the problems)