what type of GPU does your Asus laptop have? Please make sure that Vista, the GPU drivers and QuickTime are up-to-date on your machine.
Nuendo 5.5 copies the preferences from an existing Nuendo 5 installation, so this could be the issue in your case.
Please rename your Nuendo 5 and Nuendo 5.5 preferences folders (also any older Nuendo/Cubase folders you might find) and restart Nuendo 5.5.
Info on how to remove the preferences can be found here: https://www.steinberg.net/en/support/knowledgebase_new/show_details/kb_show/removing-the-preferences-of-the-sequencer
If the problem persists please get in touch with me via the Support Request Form and we can take a look at your system.