Computer acting up seems like it could be malware or virus.

I suspect I might have malware on my computer so that is why I'm posting here. I recently downloaded from the internet a updated version of Kaspersky Internet Security. I first deleted the existing version of Kaspersky Internet Security before downloading the new version from the internet. I have been having some issues with the computer before downloading this updated software. For example when running Internet Explorer 11 it takes longer than usual for a program to load. Also, when I click on a video to view from Yahoo News for example, the cursor flashes from the cursor line to the hand in a very rapid fashion.
The strange thing is the problems I have are sporadic. It doesn't matter whether I'm using Internet Explorer or Firefox each browser has it's own issues it seems. The problem in Firefox is the browser has shut down a couple of times without warning. It doesn't seem to matter where I am or what I'm doing on the internet at the time. But it shuts down and then reboots itself or it asks me if I want to go back to the prior session. I have scanned the entire computer with the new version of Kaspersky's 2015 Internet Security, using both browsers. I've done the same with Malwarebytes using both browsers.
Thank You



Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: Intel(R) Core(TM) i5-2450M CPU @ 2.50GHz, Intel64 Family 6 Model 42 Stepping 7
Processor Count: 4
RAM: 4002 Mb
Graphics Card: Intel(R) HD Graphics Family, 1809 Mb
Hard Drives: C: Total - 593551 MB, Free - 532815 MB;
Motherboard: TOSHIBA, PEQAA
Antivirus: Kaspersky Internet Security, Updated and Enable