Is this some kind of virus? Help me!

[jogabonito]

Guys I bought a new PC in december 2014 and it was working great until today.
Yesterday something weird happened, from out of nowhere I've noticed a new icon on my desktop called "homegroup"(I don't share my PC with other people beside the WiFi that I share with my neighbor).
Today when I woke up I checked my PC, it was working just fine. Before I went to school I clicked on "update and shutdown" button.
When I came back home earlier today and turned my PC on, the "homegroup" icon was not there, I just ignored it and proceed to open my browser. I was on the internet watching a video when I got a message from my antivirus(panda 2015, that I've been using for 15 days now) saying that it stopped working because one of the files of the antivirus was corrupted/missing.
The panda icon vanishes from my desktop after that, I then proceed to click on my malware cleaner(malwarebytes), it shows me another error message I close the message and the malwarebytes icon just vanishes right infront of my eyes, the same occurs with my torrent manager(no i havent downloaded anything this week yet).
I've tried to download other antivirus, the download finishes but the installer can't be found nowhere(apparently only .exe files are having this problem, I can download a picture and open it but if it's an .exe file it just doesn't show up in my PC).
My computer now is taking more time to shutdown and to turn on and sometimes it's freezing.
I've tried to use safemode but I can't find this option(MSI Bios)
Now I'm browsing just like I was before, I can open sites and watch videos but as soon as I try to open any program, it gives me a different error message or it just won't open.
Please help me guys, thanks in advance.
PS: Sorry for my english

Update: Videos are lagging, sound is not working anymore

 

[RaklopGaming]

First of all, you cannot choose to boot to safe mode in BIOS. To do that spam F8 while system is booting(BIOS splash screen).
Second, this seems like some sort of trojan and/or HDD failure signs.
While you are in Windows, launch cmd.exe (start button+r, and then type cmd.exe),
then type chkdsk /f C: (or whatever your OS partition) is and wait for it to finish.
If this does not help, I am sorry, but backup everything important, and reinstall Windows.
Inform us about the results ASAP.
Good luck!

 

[RaklopGaming]

Second option is to get the PC to some certified technician, who will detect and, hopefully, solve the problem.

 

[jogabonito]

First of all, you cannot choose to boot to safe mode in BIOS. To do that spam F8 while system is booting(BIOS splash screen).
Second, this seems like some sort of trojan and/or HDD failure signs.
While you are in Windows, launch cmd.exe (start button+r, and then type cmd.exe),
then type chkdsk /f C: (or whatever your OS partition) is and wait for it to finish.
If this does not help, I am sorry, but backup everything important, and reinstall Windows.
Inform us about the results ASAP.
Good luck!

I tried to check my disk and it says that I don't have permission for that. Now my only question is how to reinstall windows with a pendrive if I can't access the control panel without the computer freezing?