Some, for me, unknown networking, firewall or bug problem. Really weird.

Hello there TechSupportGuy members! I'm new to the forums and need help with some really bizarre problem I've had a couple of times with my computer.

Just gonna list a few of the symptoms I've found so far.

• Steam is unable to connect to the Internet, despite any ports it uses(both TCP and UDP) are open in the firewall and modem/router. Reinstalling works, but the error still occurs after.
• Minecraft multi-player does not work. It cannot find any of the servers which my friends are currently online in.
• Browsing for web pages takes a really long time, Tech Support Guy website took about one minute to load. Hotmail two minutes.
  The internet connection speed is around 14 Mbit and YouTube can stream video at 480p without problems. Actually loading the webpage takes a long time though.

I have looked through the firewall and have tried disabling it, but the problem still persists.
The only solution I've found so far is reinstalling Windows, something I'm not willing to do again since this is the third time the problem have occurred and I have nowhere to backup my 1 TB of data.

I tried making a post on the Steam discussion forum, but no one has responded this far, and I kind of doubt they will. And since it's more than just Steam, and it doesn't seem to be a problem with my router/modem, it's probably better to post on a general tech support forum instead.

It seems to be a very rare problem, but I hope any of you have some ideas as to what the problem is.

Stripe103