i wonder if something in your PC has become unreliable like your RAM etc.
a decent idea i would consider is running Prime95’s ‘torture test’ to see if your PC is stable after hours of constant use (i.e. no errors or warnings) … usually though from what i hear if it’s going to fail it will fail probably within 30min-1hour or so.
if it passes that and you still get errors i cant say for sure but a format of the PC and fresh windows installation might not be a bad idea… especially if it’s been years since u last did it or if your PC is loaded down with all kinds of software etc etc.
p.s. im just assuming your right and that your burner and discs are fine.