Compatible DVD decoder

I can't use the DVD player because a compatible DVD decoder is not installed on my computer. What can I do?

 

I have been playing DVDs on my Inspiron for two months, however yesterday I installed a Premium edition of Nero 7, but I just removed because I got a Blue Screen of Death with the error message 0x00000022 about incompatible sotfware, and now I cannot play DVDs via Windows Media Player, RealPlayer, Power DVD, Nero or Dell Media centre. Depending on which program I run I get a message that no DVD encoder can be found, however when I run the "Windows XP Video Decoder Checkup Utility" I can see and mpeg2 DVD encoder (CLVSD.ax by CyberLink) but this Utility said "This decoder is compatible with Windows XP media Center Edition; however, it is not compatible with the synchronization of Windows Media Player 10". What can I do for to use Nero without an error message?