Dvd burner-- burn & playback problem

I have used this burner and it has worked fine. All of a sudden things are not burning properly. I replaced the burner and have reloaded all software, still no success. So I got a regestry clean program and have cleaned the restry and then I uninstalled all software (nero–Clone DVD2) and then re-installed. The burner not burns the DVD all the way to the end and either program(NEro–CLone DVD) states that the DVD has been burnt succesfully, but when I go to play the computer does not recognize the DVD and when I do an explore in My computer the computer acts like there is nothing on the DVD.. Can someone please help me..I have been told it must be a conflict between some other software I have loaded, but i have no idea how to even go about figuring out were to start!!! Thanks

What you should try first, Free up some memory. Don't multitask, disconnect from the internet and turn of any/all spyware, AVs. Make sure you are not burning too close to the edge of the disk (do not have overburn enabled), make sure the DVD is 4300mb or below in size. Turn down the burn speed, What kind of blanks are you using. (maybe a change is required).

Thanks Stem I will give your suggestions a try.