Bitdefender said I had a virus, then it told me if I wanted to reboot. I said 'yes'. Then it felt like I wasn't alone anymore on the computer (Windows 8.1), and a big image turned up looking like this

- but not quite. It was more colorful. The image was alright and nice, but the rest was looking very amateur-like with a black arrow-pointer, and a pointing hand (never seen that before). A distorted text showed up and said 'Bitdefender on demand antivirus scanner', and 'copying antivirus engines'. I think it sounded so weird, and turned completely off the computer. I'm now using the old and sloooow one with free Avast, and Home Vista Premium.
Please tell me I'm not hacked...