Un-install windows home premium 64?

Sup peoples? Im running a Dell XPS 730 w/6GIG RAM, Intel i7 Proccessor, Vist Home Premium 64Bit. I was unsuccessful in my last attempt to dual boot Windows Home Premium 64 and Windows XP 32. The last thing I tried was running Windows XP 32 in a Virtual Window on Vista 64. However my programs do not function correctly in doing so. I am ready to throw Vista out the window.... However I am unable to install Windows XP. After inserting the disk and running the setup, it fails to see any drives to install XP. I have crossed this road before, and was informed to change the BIOS settings to adhere to my needs. I am not too familiar with the BIOS... I am not running RAID setup... In the ICH Config, it has an option to switch between AHCI and RAID, however when I change it and retry it fails to see any drives as well.... At this point I just want to wipe my hard drive clean, and install XP. One thing I forgot to mention was that when I had my external hardrive plugged in it was viewable, however cannot support and OS. It was of "FAT32" file type. Any suggestions???? PLEASE HELP....