Slow burning, buffer problems?

my burner is LG GCE-8523B, in my previous windows installation (xp) it burned fine until one day the burning started to take 10 min instead of 2min and the computer worked very slow, i noticed that the read buffer and the cdrom buffer level were low, they climbed up slowly and then a sudden drop, after i installed windows again the problem disappeared, but after not a long period it has started again
this is getting annoying.
(i know this is not the media’s problems because i have tried several types).
i also tried closing all the applications, i even had 180mb free in my RAM and i have 1gb free at C: drive, i simply cant see what is wrong…
(i use nero 6 Ultra)

thanks in advance, Haplo.

edit: i also tried disabling my anti-virus.

Try these two things.

DMA was already enabled and the other thing didnt help
thanks anyway
if anyone has any idea please help, im getting hopeless

I have similar problems when my hard disk has less than 2-3 gbytes. Try to free up some disk and defrag it.

i would also say, defrag the disk, this can solve your probs