Can Burn Dvd's but not read them

[2JJR]

Hi, I have a weird problem with my acer aspire 1357lmi. If I want to burn a Dvd-r with nero bruning rom 6.6.0.3 he will burn it with no problem but if I want to read it or watch it afterwards he says no disk inserted??? If I take the same Dvd-r and put it into my other pc he reads it with no problem. An other problem is that the notebook can read every dvd he didn't wrote.
Any ideas?
Thx