The plugins you are liable to need with ScotlandsPeople site are viewers for the images. If you have a problem getting/installing those you can still choose the download option for any images you wish to view. The downloaded images will be in TIFF format and, especially if you use Microsoft Windows, you should have a viewer for those. If not the free viewer IrfanView can be recommended. To view images before download SP needs either of 2 viewers, Prizm “ActiveX”, and the ViewONE Java™ applet. Once you register with SP you can use My Details menu to check your browser for compatibility. It is a long time since I registered and I can't remember if you are offered the option to install the SP compatible viewers from the SP site. Someone else will have a better memory. Persevere and Good luck. A quick check on the 1841 Census came up with only one Charles Goodwilie, in Strathmiglo, age (rounded) 40. Two others there ages 6 and 0. By 1851 there are 2 aged 55 in Kinghorn and Strathmiglo. However the 1841 Census records for Collessie were lost in transit to Edinburgh.
Dod