I'm sorry about the issue. What's the version of it?
Can we do a remote support session, so I can troubleshoot the issue directly on your computer together with you?
Please reply at the box below. Thank you,
You can try copying the content of the system mechanic application from the DVD disc to a folder on the computer, then right-click the Setup file, then set the Compatibility option there, and then open it, and see if it lets you install. However, it may not work since version 7.5 is very old. Some old programs are not compatible with the latest Windows version 10, so you would need to buy the latest version, which is 14.5 for System Mechanic.
However, if you'd like to, I can provide some alternative programs that are free. Please reply at the box below. Thank you.