For example my Sony and Dell have those apps for download at the company sites. So for those machines a clean install works great. But then again an owner challenged by not looking for such would be best off trying to upgrade the OS.
Your last question is also one that could only be answered by TESTING both methods and BENCHMARKING the results. Since no one has done that I'll write that anecdotal evidence points to clean installs followed with finding and install all drivers and helper apps (like Dell's quickset and Intel's Rapid Storage Solution) points out that clean can win.
As the 32 to 64, 32 to 32, 64 to 32 and 64 to 64 bit question has been covered many times, I'll leave that question as answered.
Thinking of upgrading from Vista to Windows 7 and trying to decide whether to upgrade or clean install. The problem I have is that my laptop manufacturer didn't supply disks with drivers, etc, so if I clean install, I presume I'll lose these apps. I've heard that the alternative (upgrading) can leave remenants of Vista which can affect the performance of Windows 7. A third alternative I thought, is to first reinstall Vista from scratch using the recovery disks (therefore creating a 'clean' version of Vista with all apps supplied when I bought the laptop) and then imediately upgrade to Windows 7. I'm hoping that upgrading from a brand new clean version of Vista might eliminate the problems associated with upgrading from a well used version of Vista. Does anyone think this would have the same effect on performance as a clean install of Windows 7?
Thanks in advance.