Hey Just Ignore it and never install it ...... I am using Build 7600 with sucessfull OEM activation Microsoft this time is taking Big steps to cure for illegal activations...
I have myself re-installed my windows 7 Build 7600 3times becoz activators available on net made windows 7 Build 7600 evaluation version with expiry in march 10,..But now i have installed successfully as OEM series..
Simply ignore this March 2010 Update and never install it..