...can't burn as my software says it is waiting for my Plex. Its only about a year old.
Any ideas please?

It might not like the media,try other cdrs, try a lense cleaning cd, try a firmware flash.
Does it recognise originals ok.

i had this prob with my x16 plex , light flashed all the time & it would'nt
read cd's , if this is your prob i think it needs to go to plextor mine
did .they replace it with new one no questions asked, took only 4 days to be replaced .

good luck m8

Ta for the replys guys.
FYI, it works if I leave the PC off for a few days but think its on the way out.