This is probably caused by a worn-out string (rubber belt) in your disk drive. This string makes the disk in your drive spin. You can probably buy a new string in your local electronics-shop. After replacement the drive will probably be fine again. But note that the VG-8235 has a Single Sided diskdrive, so you can only use Single Sided disks.

The belt size you need is 60 mm diameter (Philips VG-8235 / NMS-8245). Seems small, but it is really the correct size. Tried it myself. My belt was named BF-60. See wiki about your MSX model, the belt size you need may be indicated.