I have an inspron 531 that I am helping a friend fix. It says 64 bit on the front of it. Or it says AMD 64 athlon x2. I take that to mean 64 bit. anyway my question is why does dell tell me on thier driver page that this system does not come in 64bit. I am trying to get the drivers because I had to reinstall his windows vista, when I put my service code in it comes up as vista 32bit drivers please help.
The processor supports 64-bit, but Dell never shipped that model with a 64-bit OS, as it cannot support more than 4GB of RAM (the biggest reason for 64-bit OS). It can probably be done however, you will just need to go to the website for the actual devices to get 64-bit drivers for them, like AMD or nVidia for the chipset, graphics, network, etc.
Although the Inspiron 531 was never shipped with a 64bit OS, it does support it. Specifically Windows 7 64bit. It even supports up to 8GB of memory. The only issue with running Windows 7 64bit is with the Away Mode device. There is no 64bit driver for this device so I had to install a null driver for it. Otherwise it runs perfectly.
Not supporting more than 4GB was a common reason for not shipping a 64-bit OS, particularly pre-Windows 7. Dell may have release a BIOS update adding support for 2GB DIMM's for a total of 8GB ... I was only going off of the manual and Crucial.com showing a max (at least originally) of 4GB.