There is a simple way of installing Tomb Raider and Unfinished Buisness. With this way you can either go the free route or the $10 route, the $10 route obviously having benefits like audio and texture enhancements you download, which to be honest isn't bad for $10.
1. Download VDMSound:
Mirror 1: http://www.megaupload.com/?d=TFHTOZA0
Mirror 2: http://www.4shared.com/file/eVCgQ0Ye/vdmsound210.html
2. Install VDMSound (choosing the complete setup) and restart your system.
3. Download Tomb Raider Advanced Installer:
Mirror 1: http://www.megaupload.com/?d=IBMH7VK0
Mirror 2: http://www.4shared.com/file/lkexBchH/tr1advinst.html
4. Put the Tomb Raider cd in your cd drive. Exit out of any autorun stuff it throws up.
5. Run the advanced installer. Pick Tomb Raider from the two options in Step 1 then click Next. You will have to go through this twice if you plan on installing Unfinished Business (picking Tomb Raider Gold instead).
6. In Step 2 choose what you will be running the game with. Glidos costs $10 to unlock fully, dgVoodoo is free but has less oportunity for enhancements, and finally the original exe. I suggest choosing one of the first two. Click Next when you've made a choice.
7. If you chose dgVoodoo in Step 2 you'll get a Step 2a. Select either 1.31 or 1.40, I chose 1.40. This works fine for me, however if it gives you problems you can run the installation again and choose 1.31. Then click Next.
8. Step 3 sets up VDMSound. Select the option to let the installer configure your soundcard. Then select the IRQ7 option, this works for most computers, but if you have no sound when running the game later run the installer again and select the IRQ5 option. Clicking Next will start the installation.
9. Step 5 is the last step. If you chose Glidos originally select the option to create a PIF file, then click Finish. If you chose dgVoodoo select the option to create a shortcut, and if you have an ATI graphics card select to disable dgVoodoo vdd mode, then click Finish.
Note: To play the game in disabled vdd mode, double click the icon for it that the program created (this brings up a pop-up box), then double click the icon for the game. Don't close that pop-up box until you have finished playing Tomb Raider.