MacBook Pro slowed down and now will not start up- flashing symbols on start screen.

Question

I am increasingly worried about my MacBook Pro. It had been slow for a few weeks (I think it may be infected with some kind of malware), slowed down even more, and then a couple days ago when I turned it on it flashed a question mark folder, a prohibitory sign, and the apple logo on the startup screen and will not go past that. I followed the instructions on an apple help page for this issue- Nothing connected to it; I even removed the apple power cord. I tried a safe boot. I reset the NVRAM. It said to try starting up from an OS install disc, but my computer did not come with one. Here's the bit where I'm not sure if I made a stupid decision; another site said that the computer will download a recovery partition if there is no install disc, so I booted while holding down C even though I had no disc. I then read that holding option on startup will allow you to choose which disc to start from- I did that, and the only option displayed is a disc called Recovery (with a number after it that I think was 10.something, presumably referring to the OS version). Does this mean I have lost access to  my computer's Macintosh HD? Have my files been lost? Unfortunately I do not have them backed up. Bad decision on my part.

Answer 1

Thanks for the quick response.
Command-option-r does take me to a screen with a spinning globe. Below the globe is a drop-down menu from which to select a wi-fi network. My network, however, is not listed. (I am now sitting right by the router, and my iPhone is on the wifi without any problem.)  I go instead to manually type it in. I have triple checked the network name and password. I have used both the WEP key, which I have always used, and something that the sticker on the router refers to as the Mac ID, which is the WEP but with two zeros before it. Still the screen shakes as if I have entered the wrong password. I'm not sure what's going on now.