1.) Words cannot be copyrighted if a word is found in a dictionary it cannot be "trademarked" ie: Windows is not trademarked as its a non-plural form of Window but per se Microsoft Windows is trademarked.

You can check for trademarks at www.uspto.gov and being a former ICANN Watchdog Board member I can say that ICANN Uniform Domain Resolution Policy requires a long process of litigation before you can lose a domain name over a trademark thats why paypalsucks.com etc are still up because its a long and expensive process.

Hope this helped!