This is what I would do if I were in your situation (bear with me here, I know you've done some of these):
- Uninstall (w/restart) - reinstall (w/restart) w/o patches
- Uninstall (w/restart) - reinstall (w/restart) w/1.1 patch
- Uninstall (w/restart) - reinstall (w/restart) (apply 1.1 patch, then 1.2 - don't skip over 1.1)
You said it works with out any patches? This suggests the patches are currupt.
- Download a new patches, following same routine as above.
Still not working? Before I go any further, I want to make sure it's my PC not the program...
- Grab another PC and try the install on that one. Since we're getting the error during the install now, it doesn't have to be a PC that will run the program, just one that will install. Although - getting as close as possible to your PC would be "experimentally" correct.
Installs on the new PC?
- Try to run it (again, it helps to have another PC similar to your own). Run it for an hour, sit and play it at that computer. Tell your wife/brother/mother/uncle that you are commandeering their PC for research reasons - they might let you use it for a while. On second thought, maybe not ;-)
Still not working? Check your directX and driver installation.
- Start->Run...->"dxdiag"
- Go to the Sound tab
- Test sound at the current level (there are four - something like off, low, med, high) - if you get a driver issue here, update your directX - or reinstall
- Turn OFF Sound acceleration and try the game.
- Check your System hardware and see if there are any '?' or '!' - and then fix the problem.
- If you just updated your drivers, roll them back.
- Defrag
- Disk check
- Memory check (my opinion: at least 24 hours of constant memcheck is needed to 'find' any errors)
- Back up your data and do a fresh install of your chosen operating system. Update the drivers, update the O/S, install the game. DO NOT INSTALL anti-virus or anything else until you know if the game works/doesn't work
There might be more stuff to try too, I had a bunch in my head before I started this, but I keep getting sidetracked by children... I know it might take a while to try all this stuff, but look at it this way - there might be a 1.3 patch out by the time you figure out that there was nothing wrong with your PC, and it's just another bug in the software... ;-)