I believe the student download is full version, but it doesn't matter because that XP qualifies you for Upgrade version whether the XP is installed or not.
So buy the Upgrade for your PC, then also use the installer to install Win7 back to your laptop to activate with the key on the license sticker.
You have to reinstall your programs whether you create a dual boot or not. They cannot run on the other OS. We also have a lot of problems with dual booting Ubuntu with Win7. You need to remove and then reinstall the GRUB bootloader to manage boot after Win7 install.
What are the exact issues on the laptop?