I am having a similar problem. I uninstalled Easy CD creator 4 from my computer that has windows XP, and now my CD / DVD drive won't even play a cd or dvd. I followed the advice, deleted the cdr4_2k.sys and Cdralw2k.sys as well as went into the registry and removed: upper filters, lower filters, cdr4_2k, and Cdralw2k. I was unable to locate the Cdudf or UdfReadr from the registry, and therefore, was unable to delete these. I ran a search and did not find either. I do have Cdfs and Udfs in the Currentcontrolset/services/ folder area, but it appears as these files are normal. I have spent hours trying to repair this problem, and will admit that I am stumped. Can somebody please help me with this? Thanks! p.s. I also installed roxiozap, and that failed to work as well.