To access the MicrcosoftOffice for60 day as trial, entering my 25 items product keys are invalid.I have this generic keys in my system but not matching the exact keys that were needed. How can I get about this? It seems like someone is already using myProduct Keys.

generic key is consider as Hacktools and will generate invalid number, if you want to use Office trial then contact Microsoft and ask them for trial product key.You could also try following website and download and install it and use Product key that will given to you. Go to follwoing website : http://office.microsoft.com/ and look for product and trial download.