First thing to do is download CCleaner free to clean up all the history and cache junk ! Then change your e-mail password and you'll stop getting so much spam and junk. I change mine about every three months and it virtually stops it. I've been using Yahoo for many years and this works. If you use Chrome, clean out your history daily also although CCleaner will do it for you.
CCleaner - Free Download - Piriform
www.piriform.com/ccleaner/download