I'm happily playing my game of LoL when suddenly some lag appears, and I think to myself, "hmm I'll restart the client, that'll make everything hunky dorry" then I click on the LoL icon and it gives me this error: "Could not load direct3d". After my rage ensued, I decided to uninstall and redownload the game which took an hour and a half, and that didn't work either.

So if this was too long for anyone to read, how do I get rid of this error message, and how do I get back to playing my favorite PC game???

Make sure you have the latest drivers for your video card.

Easiest would be to just to go your card manufacturers website, download the drivers for whatever model card you have and run the updater.

If you're unsure of your cards model go to:
"Start" > in the "Search programs and files" dialogue box type "dxdiag" > and in the window that opens click the "Display" or "Display 1" tab.

Post what's listed under "Name:", "Manufacturer:" and "Chip Type:", and someone will get you a link to your driver.

Name: Intel(R) G33/31 Express Chipset Family
Manufacturer: Intel Corporation
Chip Type: Intel(R) GMA 3100

Please someone help me out!

I'm sorry, but you're using integrated video. The minimum requirement for LoL is a GeForce 8800 or equivalent video card, which the 3100 doesn't come close to.

You can try downloading whichever of the following updates applies to you, but no guarantees:
32-bit OS: http://downloadcenter.intel.com/Deta...+3100&lang=eng
64-bit OS: http://downloadcenter.intel.com/Deta...+3100&lang=eng

Neither of them worked :/
Looks like I'll invest in a new video card I guess