GRR....saved files are gone

I hope nothing happens to the vlogs i have here and uploaded on blip.tv because I mysteriously lost all my videos that was on my harddrive..not to mention ALL my pictures disappered...odd thing was the computer was making this funny noise, was showing that it was doing something then the computer turned itself off (i dont have it to do that) and then when i booted it up again all my files were gone..well the pictures and the videos anyway. SO I dunno what exactly happened but I think somehow someone hacked on my computer and deleted my files!!! UGH!!
I can't just turn my connection off when im not on the computer because of my "vonage like" phone...well its called mypeople and it works really well, heck of a lot better than Vonage!

I am pretty sure i have the firewall and stuff up it comes pretty much with the internet connection but I can't explain what else could delete files...

this is nerve wrecking!! I really really want a flash drive! That way i can just take it out when its not in use...