plz help me find a way to fix my cd burner.

When i put in a cd WR it reads it fine ready to burn. When i put in a dvd it reads fine (can read dvd's) but when i put in a normal cd w it speeds up, then slows down, then speeds up, then slows down, then speeds up, then slows down, then flashes a light and the status nays not ready. In my devices it has 1 unknowen device. I try to delete it and it comes back up

things i have tried:

re-installing all the software (also deleting the hardware configs for it)

re-formating my computer (with system disk. this may get all the configs for cd rom devices loaded back on there anyway)

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now i have resorted to asking you plz help me.


note: it worked at one stage