Thank you for your continued support. The only think I can find on the Router setup is under the WPS setup (Screenshot attached). I am not sure if that is what you mean.
I have checked the laptop's Intel WiFi adapter properties in device manager, and I can't find any options there to extend the password to more than 8 digits. I don't think Vista has any problems allowing passwords more than 8 digits. I think that the problem is because this is an older laptop WiFi adapter running WPA security (not WPA2) which only allows an 8 digit password. I cannot see a WPA2 option in the settings. My laptop has some but not all of the options mentioned in this link:
Advanced Intel® Wireless Adapter Settings
Actually, the laptop belongs to my father in law. He does not have internet and gives it to me every 2 or 3 months to update some programmes. So I had to return it yesterday. I will do some more tests the next time around. The simplest solution I think is to just reduce the router password to 8 digits and then adjust all the other devices in the house. Then hopefully, the laptop will connect to the WiFi network.
Thank you again for all your help.
Kind regards
Chris