I have a Samsung laptop running Windows 7 64 bit that is about three years old. It has been running fine, but four days ago youtube videos stopped loading properly. They will start, run for about 5 seconds, then pause for a minute or more before loading another few seconds. Amazon Instant Video also shows a connection speed of one bar and the video quality is terrible. I suspected an issue with Adobe Flash player, so I did a clean uninstall and reinstall. It didn't fix the problem. Java reinstall also did not help. My internet speed is good, ping is very low with no packet loss. For some reason, if I have adblock disabled the ads before the videos run just fine, but the videos don't.
I was using Chrome originally, but switched to Firefox after reinstalling flash (I also removed all Firefox plugins). The problem stopped for a few hours, then started again. I ran a full scan in Malwarebytes and it came up clean. My ISP showed no problems on their end. I freed up some hard drive space because I noticed I was running below 10%, the problem again stopped for a few hours and then started again. IE is also having the same problem. I have 4GB of RAM, so I don't think that is an issue.
I've tried everything I can think of. I have a friend who is a software engineer and he says it may be necessary to just nuke it and do a full Windows reinstall, but I want to avoid this if I can. Does anyone have any suggestions?