Getting rid of the checksum error issues is fairly easy:.
To uninstall a program from Windows 7:
1. Navigate to the Windows start menu by clicking on the Windows logo (Start) button.
2. When the Start Menu opens, select "Control Panel".
3. Depending on your view options either click on "uninstall a program" or "program and features".
4. When the programs and features window opens select the program your want to uninstall from the list and click on the "Uninstall" button.
5. Confirm that you want to uninstall a program by clicking on the "Yes" button.
Warning: Your PC might need to restart while following these steps. Please save and close any documents you may have open before you start.
Note: You may need to run this process more than once to download all available updates.
Load Windows 8.
On the 'Start' screen move your mouse cursor over to the bottom right hand side of the screen.
This will display a sidebar with a list of options. Select 'Search'
A screen will appear with all your installed apps, select 'Control Panel' from the 'Windows System' list.
When the Control panel loads select 'System and Security'
Then select 'Check for Updates'(this can be found in the Windows Update section.
Then select 'Check for Updates'
Windows will start searching for updates.
Once Windows has finished searching for updates, a button will appear giving you the option to update. Press this, Windows will then install all the important updates.Your computer might need to restart during this process.
If you're still having issues running your Windows-8-compatible game after updating, it's recommend you check for Windows Updates again as some updates are needed before other updates become available.