Can't get into some websites using Safari (7.0.3). Just getting a blank screen. How do I fix? Using OS X 10.9.2 Maverick.

Bought my MacBook Pro back in October of last year and so far not a fan of Mac. I've taken my laptop into the Apple store to run diagnostics and they found nothing. Now they want me to bring it in to reload everything (which means I have to back it up (and purchase and external hard drive) or lose everything). Never had these problems with my PC's. I've been having issues getting into certain websites (after I had been in them before a few times). I usually get an error message from the site (which is not descriptive enough to give you an details) or a blank page. It's very frustrating. I've cleared the cache, deleted the cookies and searched the web for hours trying to find a resolution. Nothing. Help so I can stop hating Mac.