Hi strunberg, welcome to Sevenforums.
Can you post a picture of your device manager settings with DVD/CD-Rom Drives expanded?
The drivers for your motherboard are located here: ASUSTeK Computer Inc. -Support- Drivers and Download P7P55D
I would recommend updating your Sata drivers as well. We need to know what DVD drive you have to offer the proper driver.
^^ Meaning: you can't install Windows, because your DVD drive isn't working?.. USB install is the alternative, if this is the case:I'm trying to install win7.
http://www.microsoftstore.com/store/msusa/html/pbPage.Help_Win7_usbdvd_dwnTool