Mac Keeps Freezing When Internet Browsing

Question

Hey guys,
I don't know if this'll help but all the threads I usually go on, the person with the problem usually gives their computer details, so:
- OS X Yosemite 10.10.1
- iMac (21.5-inch, Late 2012)
- 2.7 GHz Intel Core i5
- 8 GB 1600 MHz DDR3
- NVIDIA GeForce GT 640M 512 MB
Well, anyways, now to the problem;-
Lately, whenever I'm browsing the Internet on Google Chrome of Safari, 100% of the time after about 10 minutes it will always freeze for about 30 seconds, then go back to whatever it was doing. It will do this a few times until it freezes for good (spinning rainbow wheel), and I actually have to turn off the computer.
In the past, I have accidentally installed an adware called Genieo, which I got removed when I went to the mac store. I'm not sure if that's come back to haunt me, or I have done something else stupid while browsing. I haven't installed any software applications recently, which has got me confused as to why my mac keeps freezing.
Also, if I'm browsing on Google Chrome and it doesn't freeze, shockwave will always crash whenever I try to view something, then it will freeze.
After this, when I try to turn my computer back on, the kernel on the white screen will always come up, which I then have to manually turn the computer off again. It usually turns on normally after a few times of trying.
I've gone onto Recovery Mode and verified my disk many times, to which it says there are no problems.
I've looked up Antivirus' for mac, and have come across a few (Avast, CamXav, etc), but I have also browsed many forums with the majority of people saying your mac doesn't need an antivirus and it will slow your computer instead of benefiting you, so I'm not sure what to do.
Just wondering if anyone else has come across problems similar, or know how to fix this. Should I install an antivirus? Should I go to the mac store (last resort)? Will reinstalling OS X or restarting then booting up from Time Machine with my external drive help?
Thanks.
-Chris

Answer 1

acpqo wrote:
Just listing everything wrong just in case these are symptoms of something and there is a solution, thanks.
The suggestions in the 2 links I previously posted did not work?
If you have Apple Care, call them & let them deal w/it.
OOW, try the following:
1 - set up a test account.  You need to determine if the problem crops up in the test account.  This will determine if the problem is system wide or not.
2 - Run Apple Hardware Test.  Make sure when troubleshooting you have disconnected all devices from your comp except for the keyboard.
3 - Run OS Recovery again.  Only this time select "Repair Disk."
4 - Reinstall the update.   Only this time use the OS X Yosemite 10.10.2 Combo Update
5 - Take your comp to your local AS or an AASP.  Diagnostic testing is FREE!