How to Clean the Temporary Directory
1. Double-click on 'My Computer' or right-click on the 'Start' menu and click on 'Explore.'
2. Find the 'Temp Directory' from its location or you may find it by clicking on the 'Windows' folder and then 'Temp.'

3. Click on the 'Edit' menu and select 'Select All,' then press 'Delete' on the keyboard.
4. Click on 'Yes' or 'Yes to All' on the dialog box.
How to have enough space for Installation
5. Delete temporary Internet files by opening the 'Internet Explorer' browser and clicking on the 'Tools' menu, then 'Internet Options' and choose the 'Delete Files...' button.
6. Empty deleted files from the Recycle Bin. On your desktop, double-click on the 'Recycle Bin' icon and when it opens, on the left pane, click on the 'Empty the Recycle Bin.'
7. Delete files in the temporary folder. Go to 'Programs,' find the 'Temp' folder and delete the files inside the folder.
8. Delete optional windows components and installed programs that are not in use. Click on 'Control Panel,' and uninstall them using 'Add/Remove Components.'
9. Use 'Disk Cleanup...' by going to 'My Computer,' right-click on the drive you want to clean, select 'Properties.' Under the 'General tab,' click on 'Disk Cleanup...' and wait until the drive is scanned. After the drive is scanned, click on the 'Disk Cleanup' tab and select the items you want to delete from the hard drive, and click 'OK.'
How to Unlock Files on the Machine
10. Close any application that is running using the 'Task Manager' and end the task. You can also close any application by right-clicking on the application you find in the 'System Tray.' Depending on the application, based on the available options, you can select 'Disable,' 'Close' or 'Exit.'
11. Reboot your computer if the computer is frozen.
12. Run the installation again after opened applications are closed. If your installation is attempted while applications are opened, it is possible to get error 1603. Closing applications and running the installation may fix the error.
How to Install the Windows Installer Service Properly
13. Update the system with the latest version of Windows Installer Service. Go to the Microsoft website and search 'Windows Installer Service engine' that is used for older versions.
14. Choose one of older versions that you have. It could be for Windows 95/98/Me or Windows NT 4.0/2000.
15. Download 'Windows Installer Service' properly following Microsoft instructions.
How to Confirm Administrative Privileges on Your Computer
16. Go to the 'Start' menu and select 'Control Panel,' click on 'Performance and Maintenance > Administrative Tools > Computer Management.'
17. Under the 'Computer Management' dialog box, click on 'System Tools > Local Users and Groups > Users.'
18. On the right pane, right-click your username and select 'Properties.'
19. Click on the 'Member Of' tab in the 'Properties' window at the top and make sure you see 'Administrator.'
How to Remove Traces of Previous Installations Manually
20. Double click on 'My Computer' on the desktop.
21. Click on the 'C' drive and scroll to find the 'Programs' folder.
22. Click on 'Programs' and click on traces of each previous installation and delete. When you uninstall programs, it could leave traces of the program behind.