Windows Vista I can't burn media to DVDs anymore.

Hello.
Okay so I am swedish and a beginner too, so if you do intend to help me out. Explain it in a way I understand

I used the search tool and did not find anything helpful, and i hope I posted this in the right forum.

This is my problem. I have been burning dvds for a few weeks now. And have during these weeks experienced minor problems: At first, when I inserted a dvd disc to burn, the computer only made repetitive sounds like it had troubles reading the disc, and then NOTHING happened. Usually I could "fix" this by closing down every program that was up running.
After a while I could not "fix" this problem by shutting down programs like i used to, I also had to restart the computer or let it rest for a couple of hours before it worked again. Now however non of this work anymore.
I've been using a DVD- R disc, and I inserted a regular CD-R disc just to check if that worked, and it did perfectly. Now how come I can play DVD's, games and burn CD's, been able to burn DVD-R (But with slight problems) but can't at all any longer?

I hope you understand what I am saying, I'm not so good at english, especially with all these complicated computer words...

 

I am using the dvd burning program that came with Vista home premium.

I don't know the english name for it but I hope you understand what I mean.

 

Okay thank you