Had this problem the other day. Basically, some optical drives don't work right with Windows 7 and some of the newer power saving functions. In my case it was a Gateway laptop with a TS-L633B drive and I couldn't find a firmware upgrade for it (there is a Dell update though) which has fixed it for other people.
So in the end what I had to do was run the following:
powercfg.exe -setacvalueindex 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0 powercfg.exe -setdcvalueindex 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0 powercfg.exe -setacvalueindex 381b4222-f694-41f0-9685-ff5bb260df2e 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0 powercfg.exe -setdcvalueindex 381b4222-f694-41f0-9685-ff5bb260df2e 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0 powercfg.exe -setacvalueindex a1841308-3541-4fab-bc81-f71556f20b4a 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0 powercfg.exe -setdcvalueindex a1841308-3541-4fab-bc81-f71556f20b4a 0012ee47-9041-4b5d-9b77-535fba8b1442 DAB60367-53FE-4fbc-825E-521D069D2456 0
which I found listed at Softpedia
This seemed to fix the problem, but of course if the customer re installs Win7, it will do the same thing until Gateway upgrades their firmware or I find one that is right for that drive.