Do you mean "format", which wipes the partition in which you're installing Windows, or just a Windows re-installation? I've never seen a reformat fail and return to the current Windows installation.
The retail upgrade version of Windows 7 permits you to delete the installation partition, re-create and format it. (That's if the machine is booted from the installation DVD.) I don't know about the version HP provides.
Are these the graphics drivers you tried?
Mobile Intel 4 Series Express Chipset Family Graphics Driver (64-bit) HP Pavilion dv4t-1400 CTO Entertainment Notebook PC - HP Customer Care (United States - English)
If you can't get into the BIOS setup, you have a problem that does not involve the operating system. It may be a hardware problem. The "green dots" bit sounds like a grahics adapter failure.