My windows 7 64bit OS dvd maker used to work fine but now it stops at 99%. Today, after wasting 50 dvds, after trying everything such as codecs and drivers issues, differnt makes of disks etc i used an external dvd burner and it workers...so probably my internal dvd burner is bad. Do I just replace, clean it or fix it. it is a Mashita DVD RAM Any suggestions..................Why did suddenly stop working