Sorry, didn't see this. Hopefully, you've found a solution. If not, F1, F2,
and F11 seem to be the most popular ones I'm familiar with. If you're getting to the start Windows message, you're definitely in too far.
My best success is to get the model/serial number and go to the manufacturer's website and go into support (most vendors have a page to do this) and enter in that number. It brings up information on your machine, and that usually has information on how to get to the restore partition.