google keyword tool help

I'm confused with google keyword tool.i researched a keyword with google keyword tool and when i click on the keyword that below the keyword tool it shows the search result for that keyword.But when i open a new browser and typed my keyword it shows a diffrerent search result.For example if i typed best laptop on keyword tool and searched it. and goole keyword tool shows the search volume for the keyword and i clicked on my keyword.a new tab opened and showed the search result.in this search result the top 5 website for this keyword(best laptop) is reviews.cnet.com,pcmag.com,techradar.com,laptopmag .com.and i closed this tab and opened a new window and i put best laptop into the google search box and searched it.the top 5 search result is
consumermate.com,reviews.cnet.com,forums.techarena .com,naaptol.com.
the 2nd search result is entirely different from first search result.why there is a different between two search result. because of this problem i can't find my competitors in my niche.help me