Hi, sorry if this has been covered before. I've been happily running NOF 4.0 for many years (I have my original CD, manual and serial number NFW-400...) but following a hard disk change (Windows 10 laptop) I've been unable to use NOF. The installation appears to go well, I enter my serial number and reset as requested. However, when I try to run NOF I get a box saying "The serial number entered for this installation is invalid...". I've reinstalled multiple times and checked the serial number carefully each time but with no success. However, if I install NOF on an alternative Windows 10 laptop all goes well. All suggestions most welcome - thanks.