ozarkopa

I see a lot of info on dual booting vista/XP: Win 7/XP, but I don't see anything about dual booting Win 7 32bit and 64 bit. My computer came with 7 home premium installed, 64 bit, with a 750 Gb SATA HD. XP doesn't recognize the hard drive, also popsup a message saying the system I am trying to install is older thatn the current operating system. Yes it is! Wanted to dual boot XP, in order to use some of my older applications. Due to the above, I got 7 Ultimate so as to be able to use the XP Mode feature. I installed a second SATA drive; did a fresh install of Ultimate with hopes of having a dual boot system. No such luck. I have to go to F12 to select boot option, now computer doesn't boot to the second hard drive when it is selected. I want to retain the original 64 bit syatem until I'm sure I can get SATA drivers for XP sllp streamed to my original XP disk. Then will go to Ultimate 32 bit and XP Pro. If anyone out there can give me some eastily understood advice (I'm 76 years old) I would be forever grateful. My computer is an eMachines ET1331G-03W, serial number PTNBA020019350C2332700. Mother board is MCP61PM-GM. BIOS is AMI PO1-AO. Thanks for looking.