Sorry to hear about your Yahoo issues. Mine was the absolute reverse, getting as many a 35 "spam" emails per day. Mostly a bunch of swindlers looking for personal info, so they can take you to the cleaners.
Yahoo was my very first (personal) email account, over 6 years old, tonight I cut the ties for good (due to the serious spam issue). I have 4 other email accounts, so I'm good.
As etalmar pointed out, are you regularly checking your email? Did you write down the details (logon name & password) during signup? If you aren't getting emails, perhaps you (by mistake) are giving out the wrong email address. One way to check, sign up for a product that requires email verification prior to using it. Also, when you joined this forum, you should have received an email from Windows 7 Forums, welcoming you.
Hopefully, you'll get Yahoo up and running for you.
Let us know.
Cat