don't understand

I am having a problem reinstall SQL Express 2005.  I had it installed, but then I unistalled it.  I have tried installing it again, but everytime I do it says that the product is already installed.  There is no instance of it in my Add/Remove Programs.  I have read the threads that relate to this topic, but they haven't helped.  I have looked at my logs of the installs, but they don't make sense neither.  I just want the program installed again, or a way to get it so that I can use it. 

When I try to manually uninstall using msiexec.exe /x <processid> I get an error saying that the package could not be opened.  This happens with all the process ids I use that I get from the log files (I have 11 logs).

 am using Visual Basic 2005 and trying to create a database, and it will not let me.  That is how I know that it is not installed, plus I can not find any instance of it one my computer.  Please help.  Thanks.

The most recent log under applications say "Error 1706. An installation package for the product Microsoft SQL Server Native Client cannnot be found. Try the installation again using a valid copy of the installation package 'sqlncli.msi'"

The most recent log under system says "The SQL Server(SQLEXPRESS) service failed to start due to the following error: The system cannot find the path specified." This is when I went under Administrator tools to try and start SQL following what another tread said.

Since this is so frustrating, I guess I should do a System Restore. I haven't done that before, so could you explain how to do it. Also, will files be lost that I have done recently if I restore the system. Thanks alot for your help.