Please focus on getting a decent Win7 Home Premium 64 bit installer to reinstall WIn7 that came with your PC. You'll need to download the latest official ISO then burn it to a fresh DVD with
Windows 7 USB-DVD Download Tool.
Check your private messages under your User name at the top of this page.
If you want a Dual Boot with XP on the same hard drive and you have an EFI BIOS, then you'll need to enable CSM or Legacy BIOS. If you don't know if you have an EFI BIOS, reboot the PC and tap the key for BIOS Setup given on first screen. Check on the Advanced tab for CSM or Legacy BIOS to enable. XP will not install with EFI enabled.
It's also best to install XP first, which I already explained but you must have not seen. So boot the XP installation disk, select the hard drive, delete all partitions if necessary, create a new partition for XP of about half or less of the drive, full format it and then install XP.
Next boot the new WIn7 installer to install it to the rest of the space.
I have now explained this twice. If you have any questions about performing these steps, ask them back. I don't want to have to type them out again, so now is the time to get your questions answered.