|The fact it only happens with disks you record makes me think the recording function on your drive has failed. The drive thinks it's recording but it's not. After recording a disk does your burner software do a scan to verify it recorded correctly?|
Possibly the drive is just dirty. You can get a drive cleaning disk. It's not as good as opening up the drive and cleaning it out but it's better than nothing.
Other things to check: Make sure the disks you're recording on are compatible with the drive--all that +/- rw and 'double layer' stuff. If that checks out, sometimes switching brands of the blank disks you use is all you need to do. You can also try recording at different speeds.
But optical drives aren't all that durable so if the above doesn't help you'll just need to buy a new one.