Please tap the F8 key during the start-up process, from when you turn the machine on. You will be presented with the Windows boot menu. Please then choose the "Last known good configuration" option and this will restore your PCs software registry to the state before you installed the application. Your PC should then start Windows successfully.
Note: If the problem only appears after you have booted the system and logged on, the Last known good configuration option may not resolve the issue.