PC works really really slow when Dvd-Burn

In the last few days I have problems with my Pc.When I am trying to burn a Dvd with Nero it is being burnt with a speed no more tha 1,5X and also the whole system at that time seems to be really slow.Even when a song is played on winamp it stops and starts.I have a Liteon Dvd-RW.
Of Course I am not sure if it is a Dvd-R problem.It may be a Ram problem or whatever else,that's why I am asking.I have 2GB of Ram and Windows Xp UE.

Did you mean Vista Ultimate Edition?

What media are you burning with?
What is the full model of your liteon?
What version Nero are you using (full version number on the help about screen please).

What antivirus and antispyware and firewall do you have?

Drive in PIO mode maybe?