1) There will be no issues if the motherboard is an exact replacement.
2) If a new motherboard all together, there is a chance you can use your old hard drive on the new motherboard. I would install the hard drive on the new motherboard and see if it boots. If you have issues, try pressing F8 and booting that way. This should where you boot up. From there I would recommend booting up in Safe Mode and use a program like DriveSweeper to remove all drivers from your old motherboard before installing the new drivers. This will help prevent conflicts.