There are 2 options:
1. Please backup your database file(leader.db) using menu Servicing>Database backup. After that uninstall old version using Start>All programs>LeaderSolutions>Leader>Uninstall Leader or using Add/Remove programs. Now you are ready to install new version using LeaderSetup.exe and after finishing of instalation just go to menu Servicing>Database restore, choose database file from your backup folder and this is it.
2. Just unpack LeaderPortable.zip file, copy all files and folders(except Database folder and Resources headerimage.png and footerimage.png if you replaced them by your images) and replace old files of your installed application.
For windows XP you need to have Windows installer 3.0 installed on your computer.
For example if your aplication is installed in folder c:\Program Files (x86)\LeaderSolutions\Leader those images will be placed in folder c:\Program Files (x86)\LeaderSolutions\Leader\Resources Just rename your images to headerimage.png and footerimage.png and copy/replace them into Resources folder. Please make your images height=396px and width=2480px for good visibility on reports.
Yes it can. Just connection string of local application should be set to database of remote computer-server on your network. One more condition should be fullfiled is to give access rights of other network users to folder where database of your computer-server resides.