Problem with Intel Core i5 3570k

[terminator363]

Today my computer has been noticeably slower than before. Usually my CPU runs @ 0.4% - 1.5% when I'm not using any applications. Today I checked speed fan and my temps are a bit higher and the CPU Usage won't go below 25% the core usage on each core seems to be jumping up and down uncontrollably.

The computer is almost a month old and I'm worried, what should/can I do.

Edit: This morning I was trying to download a plugin for Firefox to use a website to monitor surveillance cameras at one of our properties. After an unsuccessful download I just kept using my PC normally. By the way, the plugin was called Webkit. A few relatives said it worked for them. It sure didn't work for me. I'll run a virus scan for now...

Edit 2: 1/4 into the virus scan my PC went into blue screen, it came back and now I'm here again. As for processes everything is at 00

 

[tuga703]

Would a look at the processes running in task manager not show what is using the CPU?

 

[bergauk]

Check task manager and report back with the program that's using the most.

 

[terminator363]

(All programs 00 for usage)

All of a sudden my CPU jumped to 40% and fell to 0.4%-2.8%. It looks stable for now. I just don't get why it was running so high when nothing was being used.

What should I do now? Should I run another scan?

 

[NissanSkylineN1]

Webkit sounds suspiciously similar to Rootkit...

 

[terminator363]

Ok, I just figured it out. Once downloading this "plugin" WebKit; regsvr.exe pops into Task Manager and hogs the poop out of my CPU. So now I know the problem but why does this happen ?

EDIT:

So every time I try to run a virus scan (Panda Anti Virus) I get BSOD.

 

[Grayfox]

Best run Combofix fromm bleeping computers.
After than run a sfc /scannow in the command prompt as admin and then run a chkdsk /f /r /b and reboot(this will take ages)

 

[terminator363]

Ok.