My laptop is having issues

[Taffy]

I was browsing the Internet (YouTube to be exact) when my browser froze, followed by windows, which led to a blue screen. No big deal, just turn it back on. It happens some times. Now, when I turned it on, I was greeted by the "boot device not found" message, which I've found easy enough to fix with a simple google search: I hit f10 when it loads, reset its boot settings, exit and go. Well, it's not working now. I got it to load up, but when I log into my computer. There's just a black screen. At first my wallpaper and the bar would load, but now nothing shows up at all. Just my cursor. I ran windows in safe mode, no problem getting it to load, so I tried a system restore. Didn't fix it. And now I'm back to "boot device not found." Help. Oh, and it's a compaq precario CQ62 Edit: forgot to mention; I keep getting an "internal battery error" when I turn it on. That was like that for a few weeks/months, though, all the battery is doing is not holding a charge.