Please help

I bought this pc off a friedn who made it for me - a few months later the cd burner does not detect a blank cd or a data cd but it will play a audio cd

So I cant burn a cd no longer. I want to install XP - So Iwas going to backup of everything but I cant becuase the burner no longer burns cds.

Also my dvd player will play the dvd fine for 40 minutes or so then after that every 10 seocnds or so it wil stop and not play then play then stop etc ---
So the CD burtner adn ddv player dont work anymore (DVD plauyer never worked)

I am going to have him look at it, but I thought Id post here and see if anyone knows anything that can cause this and also any other way to back up your stuff??

Thanks

My pc
is currently windows 2000
80 GB HARDRIVE
1 GIG RAM