No CD/DVD drive on windows7

From the way you phrase your question it sounds as if this is a new prob associated with installing Win7. I would check that the drive is appearing in Device Manager (assuming there is one in Win7) and see if there are any problems noted by Windows -- and follow help.

Also look at the drives properties and make sure that the drive is shown as a burner -- there may also be reference to whether it's set as a burner within Windows Media Player.

If the issue was a problem before Win7, I would check the cables and make sure that the drive's jumpers are set to Master -- if it's the only device on that cable.