Open Control Panel> Add/ remove programs. Show windows updates. There should be a list of updates and/or service packs that are currently installed on your computer. Many updates over the years are superseded by newer updates. All you should need are the ones listed there.
Make a list of those files and then in the Technet link I provided you can type in the KB****** file number to get that download.
I don't know of any way you can save installed updates unless they are currently in your download files.
Looking at your original post I wonder why you can't fix what is wrong with your current installation.
Have you tried to troubleshoot the current installation?
Are you sure the issue is NOT hardware related?
How long has the current installation been running?