Is this the misinformation board?
Every new operating system has minimum system requirements. If your computer is too old to meet the minimum system requirements, yes, one of your choices is to rebuild your computer if you don't outright buy a new one. Even OS X has minimum system requirements as much as Apple's marketing department wants you to believe otherwise.
Yes and no to compatibility of older applications. Some programs work and others don't. If you're running on a modern operating system, you should already be running 32-bit programs. Vista has several compatibility mode options to run older programs.
I'm running Adobe Creative Suite 2 and there are few problems that I've seen so far even though it's a 32-bit application and I'm running in a 64-bit OS. I haven't had to run any compatibility mode options yet on the software. You'll need to contact the vendors of your older software to check with them whether they are Vista-compatible.
So far, the only program that I've had to run Vista's compatibility modes for is a program called Joost but the program is still in beta so that's expected. Once it gets released to the public, I expect it to be fixed. One program that I do have a bug with is Adobe Acrobat 8. Everything works fine except the Acrobat printer but that's expected since that requires a printer driver for Vista which Adobe hasn't made for 64-bit OS' yet. Again, most people buying Vista today are buying the 32-bit edition so you won't have the same problem I have with Adobe Acrobat 8. So again, the answer is, check with the vendors of your older software for compatibility. They may have already released a compatability patch that you don't know about.
