Diagnosing problems

[Glendor]

In the last week I am having major issues while playing games or watching streams, sometimes even youtube is giving me trouble. I have tried to run virus scans, malware scans, and defragmentations. Basically everything I can think of. The last time something similar to this happened to me I replaced my power supply thinking that it was too small and it fixed the problem.

Now I am wondering if if could be another component in my computer.
Specs:
i5 2500k
EVGA Geforce 560 ti
16 gbs 1600mhz ram (I know this is overkill)
650W corsair bronze series PSU
I cannot remember what my motherboard is, though it is a gigabyte somwhere in the 140 dollar range.

I also have two monitors though turning one off while playing doesnt seem to have an affect.

Could it be something like my graphics card has gone bad? I have only had it for maybe 5 months. Everything that I play recommends the highest settings possible but they arent working I currently have starcraft 2 at medium graphics and it is lagging. Also could it be my internet? Whenever I run speed tests though it says I am fine. Any help is very much appreciated.

 

[OS-Wiz]

Latest vidcard drivers installed? Power cable(s) to vidcard secure? Heat is another possible problem.

 

[OhSnapWord]

Try cleaning all dust from inside the system, paying special attention to the graphics card.

 

[Glendor]

Ok my computer seems to have fixed itself. I am still going to clean it out as that just sounds like solid advice and check on the drivers.

However if anyone has any other idea of what caused it for future reference that would be great. Possibly it was my internet and I was having connection issues?