Explain your problem in more detail. Reverting to Windows 8 is not really a viable option as it will automatically re-update to Windows 8.1. There are multiple problems with the way the update is pushed and I recommend performing a direct clean install. See here to download a Windows 8.1 with Update 1 .iso:

http://dellwindowsreinstallationguide.com/download-microsoft-windows-and-office/

See here for instructions on clean installation:

http://dellwindowsreinstallationguide.com/a-clean-install-of-windows/