DirectX error while installing Nero7.0

I have purchased Liteon DVD/CD-RW few days ago and when I try to install the Nero 7.0 to burn the DVDs it tells me to update my DirectX 9.0c version.[but I already have that version on my PC] and if I still allow it to check for update in DirectX gives me this error [Pic below] that it cannot update.My XP is genuine and my driver cd's are also genuine....I also want to note that I already had Nero7.0 installed in my computer and I am trying to uninstall it from my PC and load the newer one, but the older Nero software does not uninstall and the newer one tells about Direct X problem...I am really frustrated please help :mad :banghead

 

this the error message I get during Installation of Nero7.....

and the error message I get during uninstallation is
""Fatal Error during installation".confused