Elisabeth, User.dat and System.dat are both hidden read only files. To find them go to Windows Explorer and click on View, Folder Options, and then View. Under "Hidden Files" make sure "Show all files" is checked. "Hide file extensions for known types" is unchecked. Click on Apply and OK. In the left pane, click on the + beside your C drive, and then on "Windows". The right pane will now display all the folders and files in C:\Windows. Scroll down until you find the files you are looking for. Personally I have never backed up any of these files just to install a program. I think some "experts" can make things too complicated. Here is my method which has never failed me yet. All I do is scan the download with Nortons and then shutdown and restart my computer. I turn off all programs except Explorer, Systray, and Rundll. -just like doing my weekly Scandisk and Defrag. I then install the program and check that it works. I then shutdown and restart and make sure that everything seems to work. Then I run MSRegclean and JVRegcleaner. Once this is done I move the download file to my archive folder (C:\Z), just in case I need it in the future. Have fun, Brendan UNSUBSCRIBE by sending email to triadtechtalk-request@xxxxxxxxxxxxx with unsubscribe in the Subject field. To VIEW/CHANGE your subscription status go to //www.freelists.org/webpage/triadtechtalk