When trying to login, the error “The instruction at 0x7c90c..memory cannot be written. Click ok to terminate (which shuts down the computer) or hit Cancel to debug. This brings the BSOD and the error STOP c00021A appears. I selected “last known configuration” which doesn’t help. For now, the user can log in if he doesn’t select the options to the first error message. Would doing a repair installation help?