You could always run firefox with a neat little add on called No Scripts which blocks ads and most other types of crap websites try to run,you then have the option of letting whatever scripts you want run and blocking those you don't want running,
Ad Block Plus is another cool add on,along with Better Privacy which removes lso (long term) cookies that your browser cleaning doesn't remove.
Down Them All is another fantastic firefox add on (download accelerator),go to a page with 100 pdf files or any other type of file and watch this baby work,cosmic.It rattles them down in no time.You can even set it too download only the file types you want and ignore the rest on that page or even just click on as many of the individual files you want from a list as every file on the page is listed on it.
Add the free C Cleaner utility and keep all the shit off your computer.
Using internet explorer is just asking for nasties on the web,because everyone just loves Mr Gates.