Assuming you can actually boot your computer up, my friend, simply type msconfig into the Search option at the bottom left of your desktop display, then remove the changes that you made. Save the changes, then reboot your computer.
If you can't boot into Windows in Normal Mode, try rebooting your computer and repeatedly pressing the F8 key before you see any logo onscreen. This will give you the option to boot into Safe Mode, Safe Mode with Networking, etc.
Repeat the above instruction about entering msconfig and making the changes again. Then resave and reboot your computer.