The Dell splash screen can be disabled in the BIOS setup menu ("Boot-time Diagnostic Screen"). If it's disabled, you should just see a bunch of technical text instead (and the 0/2 prompt). So, a missing Dell splash screen doesn't necessarily indicate a problem.
Try holding down the zero key right after
turning the power on (or go nuts hitting it a million times). You should get to "Boot Menu", with entries like "Hard Drive" (the SSD
), "Diagnostics", "Enter Setup", etc. If you see a flashing cursor, GRUB or Ubuntu, you were too slow to hit zero... or you have a BIOS problem. But I think a BIOS problem is unlikely.
If it worked, boot off a USB drive and see if your wifi card is present.
As for your problem with startx/root-recovery etc, some software is screwed up. It might end up being easier to back up files and reinstall the OS, but you can try reinstalling/reconfiguring important GUI packages first. I dunno, maybe "sudo dpkg-reconfigure gdm" or "sudo apt-get --reinstall gdm". Something like that.