Problem with Nero 6

Hi everyone here
I just try to use Nero6 to burn a couple of discs [cd].
After burning successfully, my computer cant run smoothly!!
It seems lagging!! Say, it cant play mp3 softly
And after i reset it, it take ages to boot up!

In fact ,it happened beforehand. I just format it in the last time.
But i really dont know to format it again coz it is too trouble to do so and restore the softwares.

Hey buddies, is it a soultion to solve it??
P.S. i have checked the AV and try to free the ram .it should be no problems related to them.

Thanks in advance!