Internet stops when playing Youtube videos in fullscreen in Chrome

Hey guys.

I've got this problem here: Whenever I play a youtube video in fullscreen, there's a good chance my internet connection will just stop, and I have to restart to fix it.

Some info:
- It happens only with Chrome, not with IE or Firefox.
- It happens on any WiFi and LAN network I've used, since it started a month or two ago.
- It doesn't happen in other websites, just youtube. It runs fine if it's an embedded youtube video in another website.
- I've scanned for malware.
- There's no problem if I'm watching videos not in fullscreen
- I've tried changing the setting in youtube to automatically change the resolution based on player's size. I've tried it also on different resolutions, but if it's fullscreen, the problem can occur with any resolution.
- I tried to switch to HTML5 in youtube's settings but it didn't help.
- I tried stopping the antivirus and firewall, but the problem still occurs.
- I tried clearing the cookies and cache.
- I tried reinstalling Chrome even with a cleaning program; no success (It's the latest version – 21.0.1180.89 m)
- It happens on different Chrome/youtube accounts.
- It happens in incognito mode (with all extensions off)

Could you help me out here? It's very annoying to have to use another browser just for watching some videos.

Regards,
Pavel

PS: This summer my brother dropped the laptop in the sand on the beach (while it was off). I opened it and clean it, but I've done that many times and I know my way around, so it's unlikely I've messed up something with the assembling. That's the only thing I remember to have done before the problems started. I don't think I've installed any software or drivers at the time it started happening.