Do you have a desktop at all? If you do, you're best bet would be to remove the HDD and plug it up to that and retrieve your files.
Otherwise, this article might help:
-http
/www.tomshardware.com/forum/279864-28-connect-hard-drive-laptop
If you need help in removing the hard drive, look up a service manual for your laptop or ask a tech savy friend to help you out.
I don't have much experience with the what will/will not void your warranty but this should at least get your documents.