Fresh install is usually best way.
Microsoft does have an program that will analize your computer to see if the hardware and software will support the new OS.
http://www.microsoft.com/windows/pr...pgradeadvisor.mspx?wt_svl=20029a&mg_id=20029b
Very good question. I remember when I upgraded from Win98 to XP, a number of programs did not work and some hardware peices were not supported. I ended up replaceing a few programs and buying a new scanner.
Microsoft does have an program that will analize your computer to see if the hardware and software will support the new OS.
http://www.microsoft.com/windows/pr...pgradeadvisor.mspx?wt_svl=20029a&mg_id=20029b