Dell Studio 1558 issues in Windows 8.1

Hi,

I installed Windows 8.1 on Dell Studio 1558, via clean install.
All device drivers are installed (like windows 8).
After windows update last night, today i noticed following issues:

1. Power options all gone. (It was also seen in Win 8.1 Preview)
2. Cann't open properties of any network adapter (wifi/ethernet/usb dongle); error: "An unexpected error occurred"

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Screen brightness issue remains same as before, no solution :(
http://en.community.dell.com/support-forums/laptop/f/3518/t/19515064.aspx
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Does anyone face similar issues or else??