The QuickTime media player has multiple security flaws that is putting your Windows computer (and if you have a Mac) at risk for malicious attack according to Apple. Hackers can create maliciously crafted movie and image files that could be used to execute harmful code on vulnerable machines by utilizing a buffer overflow error.
QuickTime 7.1.3 has been released as a high-priority update. This update fixes all the recent known vulnerabilities. If you have not already updated your computer, I would highly recommend that you download it and update it now.
Bonus Tip: If you select the 'QuickTime 7.1.3 for Windows 2000/XP' option on the download page, you can get Quicktime without iTunes.