While trying to install Office Web Applications on SharePoint 2010 which has been installed on Windows 7 you received an error message that states:
-A system restart from a previous installation or update is pending. Restart your computer and run setup to complete.
-Windows Server Features or Role Services required by this product are not enabled.
If you check the "Wac Server Setup (*).log" files located in the %TEMP% folder you will notice an error which has a hard coded path to an .exe which does not exist.
Under Windows7 you will not find ServerManagerCmd.exe in the System32 folder.