Error when installing - "TRL Demo can only be played on a PC that supports the SSE instruction set, which isn't supported on your PC." -- PC is too old and does not support the SSE (or 3DNow!) instruction set that was introduced on the Pentium III processor.

CRC Error when installing downloaded TR7 Demo -- The file has become corrupted during transmission. Try downloading again from a different site.

Unable to access archive.dat when extracting downloaded demo files -- This error was reported when using WinXP Zip Wizard. Try using a different method to extract the files. (WinZip or WinRAR)

Install Error - trl.dat could not be found -- Disable your antivirus protection program before installing the game (reported for NOD32 antivirus system). Don't forget to turn it back on afterwards!

Static noise from music and ambient sound in the game. -- First check that the latest sound drivers are installed. If problem persists, then disable the hardware acceleration on the sound card. Control Panel > Sound & Multimedia > Audio Tab > Advanced > Performance > Slide bar to None.