First, go to www.tombraiderchronicles.com go to the game section,go to either of the tomb raiders 2 or 3 pages, and download the VIsta XP multipatcher (if you have windows 7 32 or 64 bit don't worry, the patch works fine.) You only have to download it once, it pathes both TR 2 and 3.
Now here is the time consuming part. The Multipacther requires you have the CD s for TR 2 and 3 in the drive. So what you have to is make your own (presuming you don't have the original TR CDs).
Simply got to the folder where you installed the games,open the forlder for TR 2 and then copy the contents to your cd rom drive and, burnt them to a blank cd. Name the CD TOmb Raider 2. Please note you copy the contents,not the folder itself;do not copy the folder to the cd just the contents.
Repeat for Tomb raider 3 on a second CD,
Now simply put the cd in the drive, and run the multi patcher. Remove the CD.When you are done, the game should run perfect. And NO, you do not have to have the CD in the drive if you using the GOG Version.
You might want to keep the TR2 CD you made around, because you can use it to play the Five extra levels also available for free (and yes, it is a legal download) at www.tombraiderchronicles.com.
It is a slight pain in the butt? Yes. Should GOG have fixed the problem before they sold the game? You bet. But the point is for about 40 minutes time and 2 CDs (probably worth about one buck for both nowdays) you can get the games worling on modern computer.
BTW, email GOG support to fix the problem. Since a bunch of fans were able to fix it with a multipatch, they should be able to do the same.