runtime error 21 at 00406127, and runtime error 87 at 00406127 multiple windows coming after after everything boots. Once I click ok then everything works. It started when I deleted 6 usb dos drivers in reg edit, because the pc was not recognising an extended partition on an external hard drive. Problem is if I put these usb dos drivers back in, then the pc will not recognise the extended partition on an external hard drive. Any advise would be appreciated.