dvd/cd-rom not working, please help

Hello, i have a HP Pavilion dv5-1138nr and since i installed Windows 7 beta the dvd/cd-rom has not worked.
The device is HL-DT-ST DVDRAM GSA-T50N. The device status is= "Windows cannot verify the digital signature for the drivers required for this device. A recent hardware or software change might have installed a file that is signed incorrectly or damaged, or that might be malicious software from an unknown source. (Code 52)".
I appreciate any help and sorry if my question is on the ignorant end.

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