Many thanks for all the good advices. It seems that the burner has started working properly again. I checked it with fixit, and then I cleaned the lens with a wet screen-cleaning tissue, and things started going smoothly again. I tested it just once, but I hope that the issue is permanently fixed.
But I think that part of the problem is that this machine is nearly 2 years old, and I have burned already lots and lots of CD’s. I take extremely great care of the laptop, however: I run disc cleanups daily, and I defragment the c: and d: units regularly with the standard windows defragmenter and also with the excellent Puran Defrag, and of course I take extreme care not to get any virus. But at some point perhaps all this will not be enough, for time passes…
How long do you think a machine like mine can run acceptably?[/QUOTE]
Alot is a mystery but if you did what you did clean the laser lens and dust out the system every year and redo the thermal paste and not block the laptop vents it should last long time. I have laptops from 2007 and I disassembled/cleaned and redid the paste and upgraded the hardware and CPU, RAM and they are running very good and without problems. As anything that is electrical will fail eventually because of it’s very nature. It could last years 5 years or more or die the very next day you power on the system. But regular O/S updates and hardware maintenance-yours will keep humming along til it retires.