I probably know just enough about scanning documents to be dangerous, but it seems to me that scanning would be the way to go. The only other way I can think of to convert an old journal into electronic files would be to photograph each page and save it as a .jpg or .png file. I doubt if that would give you very good results.
If you have a scanner hooked to your computer, you should be able to find a 'Settings' menu that will let you choose the resolution of the scans, the file format you want (I'd suggest .pdf), and where to put the files. You can open a new folder on your desktop and put the files there if you wish. (I don't use Paint, and I'm not sure what file formats that supports or what it does with your files.) If you're not able to get it going, you can probably take your journal to a local copy shop and get them to scan the pages for you. The cost per page (or perhaps a one-time startup charge, plus per page charge) shouldn't be all that outrageous. Take your flash drive with you and have them put the files on that, then you can transfer them to wherever you want.