I have a Windows 7 64-bit machine. I downloaded a (paid, legitimate) copy of Microsoft Office 2010 in ISO format. I followed the directions provided, first using 7-zip to unpack the ISO and then, when that didn't seem to work, WinRAR. But I kept getting an error message saying "OSETUP.DLL digital signature does not validate or is not present".
I then tried mounting the ISO (using SlySoft Virtual CloneDrive). Everything mounted correctly, but the error message persisted.
I read several help forums and apparently this is a common problem (going back to Office 2007), but none of the recommendations (including from the Microsoft support staff) have worked.
It's been over an hour and I'm running out of things to try. Any suggestions as to what might be wrong?