My laptop is acting up with any internet connection. Help?

[379]

My computer seems to have a problem with internet connections. I know that it's not my router because my computer acts up the same way when I use the internet at other places, and my phone and other devices work fine with those connections. Here's what's wrong:
Suppose I'm on YouTube, when I'm on the front page, a good portion of the pictures on the page won't load up as thumbnails and just show a little green/white icon. And then if I watch a video, I can't even watch 30 seconds of the video without it crashing with an error message.
The same stuff happens with other websites too. I haven't been able to download anything or send large emails lately on my computer. I still can through my phone, so that's how I know my computer is the problem. I can still browse the internet and stuff, but it frequently doesn't load the page properly and I have to refresh it, and I can't stream anything or download stuff right now.

Can anyone please tell me what could be wrong with it? I don't know if it's a software thing or if it's a problem with one of my laptop's parts.
Thanks for any help!!

[Charles2015]

Do some maintenance on the computer if not done already.
Try defragmenting the drive and run some cleaning software. The hard drive should not be full or close to it. This causes problems.