All drivers that came with your computer are probably stored in C:\Dell\drivers. The rest of the C:\Dell folder contains programs that came preinstalled with the computer, but I never keep those, they are crap. You can also go to http://support.dell.com/ to get the latest drivers for your PC.
You can donwload an official Windows 7 install disk from here:
You must get the right version (i.e. Home Premium, Professional or Ultimate) since you will need the product key sticked to your computer to install it. You can install that version of Windows in any language, and 32-bit or 64-bit, with the key for your PC.
But probably you have a recovery partition from which reinstall is much simpler, try pressing repeatedly the F8 key before the "Windows is starting" message appears, then select "Repair your computer".
And if you can't boot, you can backup your files with this: