I have a Dell Studio 1558 with a i7-740 CPU. A few weeks back my hard drive failed so I called Dell. After changing the hard drive, the Win7 disc kept installing the 32-bit version no matter what the tech support person did. The disc simply refuses to install a 64-bit OS even though he was sure it was the right disc.
Now I have a 32-bit Win7 without any of the proper drives installed since all the drivers on Dell's website are in 64-bit. That means no wireless/Bluetooth, no displaying in native resolution, no Aero among other things. Odd thing though, Windows does recognize 6GB of RAM even though only 2.93 GB is "usable". I would really like to install a 64-bit Win7 so any help on this issue would be greatly appreciated!
Someone correct me if I'm wrong, but I don't believe there are any Windows install discs that have both 32- and 64-bit versions on them. If the disc you're installing from gives you the 32-bit version, it must be the 32-bit disc. I think you're going to have to ask Dell to send you a 64-bit disc to use...
32-bit comes on one disc, 64-bit comes on another. I believe the Retail box of Windows 7 comes with both discs.
If you only have 1 disc and it's installing 32-bit then you have the 32-bit. You will need a 64-bit disc (and ignore what the tech support person says because they're generally idiots who follow a script).