The main reason for crashing Internet Explorer 9 when you open YouTube or similar sites is incompatible extensions, especially download manger, YouTube video downloader (BHO) and old display adapter. As in Firefox, IE9 has no built-in option for automatically checking incompatible add-ons. Therefore, some Add-ons installed in IE7 or IE8 may become incompatible after you upgraded to Internet Explorer 9 (IE9).
Following are few methods to find out and eliminate IE9 crash. First, try YouTube or any problematic site by disabling all add-ons and extensions. For that, Right click IE9 icon and select InPrivate Browsing. In ‘InPrivate Browsing’ mode, all toolbars and extensions are disabled by default.
If Internet Explorer 9 no longer crashes, try disabling extensions one by one, especially BHOs of download manger, YouTube downloader, etc. In this way, you can identify the problematic add-on and disable it.
If the problem still persist, try resetting Internet Explorer altogether by going to Network And Sharing Center - Internet Options – Advanced – Reset.
Another reason for IE9 crash is incompatible or old display driver. To solve that, go to Network And Sharing Center - Internet Options – Advanced and check the option Use Software Rendering Instead Of GPU Rendering, then save the settings.