Switch users screen popping up... Virus?

[dkplayaclub]

Whenever I start up my PC I am able to use all of my programs without incident, however when I open any web browser and start typing or following links my monitor goes blank. Then when I input anything the lockout/switch user screen pops up. I enter the password and everything resumes, but then I only get about 2 seconds to browse before the same screen pops up. This will happen over and over again and it's quite frustrating.
I have scanned my computer with Malwarebytes and Spybot in normal and safe modes and neither found anything so I am usure what could be causing this. Any advice would be helpful.

 

[Miranova23]

What kind of computer is this? Laptop/desktop? Brand/model? I ask because I recently was a victim of nVidia's defective GeForce GO 7400 in my Dell XPS M1210 laptop.

There is definitely something screwy going on inside your OS, but it might be hardware-related causing the problem.

 

[dkplayaclub]

Sorry so long to get back. Been a busy few days here. I was able to solve the issue. All I did was reset my router to factory defaults. I got the idea because I suspected someone of messing with my network to spite me.
This seems to support my theory of malice but I can't think of what setting could cause something like this.

By the way, this is a custom built desktop PC on a network with 6 other computers.