So I'm running a "clean" installation of Ubuntu 13.10 and although I can see the login screen just fine, I immediately get a plain, black screen after entering my credentials (not even the cursor is shown)... Quite literally the only thing that was changed (besides the initial updates for Ubuntu 13.10) was the graphics card driver - I changed from the default (Open Source) driver to the propriety one.Therefore, I suspect this is is my issue and I just need the applicable commands to revert back to the Ubuntu default (feel free to correct me if I am wrong however), which I imagine I would input via the "recovery mode" of Ubuntu?I tried a couple of commands I found on here, though I couldn't tell you what they were - our 'net has been down for a week and I was reading off my itty-bitty smartphone screen.I'm rocking a Sony VAIO VPC-CB15FG with a hybrid AMD Radeon HD 6630M/Intel HD Graphics 3000 card.