Dual boot Linux with Windows 7
Solution 1:
Download a live DVD/CD/USB .iso file from one of the many Linux websites and install a new GRUB. It should detect all existing and installed operating systems and include them in the boot choices. There is a good tutorial on the GRUB here... http://www.gnu.org/software/grub/manual/html_node/index.html#Top
Solution 2:
If you have PearOS installation CD, I think there should be option to repair boot loader on that CD. So, boot from that CD and choose boot repair. I had similar situation with Ubuntu and GRUB loader.