If you cant restore the registry using system restore there is no other way if you didnt back it up firstly, so forget that. If you go to device manager and expand system devices you should be able to find the name of the chipset.
Firstly can you find this in device manager DVD/CD-ROM drives
if so do as follows :
In Device Manager, expand DVD/CD-ROM drives, right-click the CD and DVD devices, and then click Uninstall.
When you are prompted to confirm that you want to remove the device, click OK.
Restart the computer. After the computer restarts, the drivers
will be automatically installed.
Try this if the above isnt possible :
Open the Hardware and Devices troubleshooter by clicking the Start button , and then clicking Control Panel. In the search box, type troubleshooter, and then click Troubleshooting. Under Hardware and Sound, click Configure a device.* If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
Post back you may have to use the repair option on the Windows 7 DVD if you have one by rebooting and starting installation.
*Did you also read what kipper said - " If the drive is an IDE drive you can also uninstall the IDE controller and reboot and let windows do its thing there also" - you would find that in device manager.