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#50
Hello EK, and welcome to Seven Forums.
It sounds like you may have previously used the SP1 Disk Cleanup Tool. If so, you will no longer be able to uninstall the SP1.
If the SP1 came already part of the Windows 7 installation in this evaluation copy, then you will not be able to uninstall the SP1.
In Option 2, you needed to open a elevated command prompt (right click - Run as administrator) instead to run the command in. The link in step 1 of Option 2 can show you more on how to open a elevated command prompt.