Major Problem - Cannot fix as IE won't open

So I think I got a trojan clicking a schoolwork-related attachment from my friend. When I clicked and ran the attachment, all these Symantec 'scanning message' message boxes started popping up on my computer, and the error messages I received indicated that my computer was trying to send virus-laden e-mails to other addresses.

Anyways, I hadn't heard of this forum yet, so I restarted multiple times and managed to run Microsoft AntiSpyware and Norton on my computer (my house has 2 connected ones, I'm using the uninfected one right now). The first time I ran AntiSpyware, a whole load of trojans and spyware popped up, so I deleted them. The second time I ran it, there was still a trojan left in a registry key. I discovered this website using this computer and tried to access IE in the infected computer in order to download the necessary programs, but I can't! When I open it, the page goes to 'about:blank', and when I try to change the address to any other webpage, I get the message that goes like 'Internet Explorer has encountered an error and has to close' and all the scanning message boxes start up again and slows down my computer very much. I also managed to access the Add/Remove Programs, and there was no new or suspicious program listed. Any help would be much appreciated!

 

Yes, I've tried opening IE both in normal mode and in safe mode w/networking, but I get the same result. It goes to about:blank and an error pops up when I try to go to another website. I've read the sticky, but I can't download any of the programs on my other infected computer because of the IE problem.

 

Right, I've ran all the programs the sticky said to, except for Microsoft Defender, which I could not install, and the online ones for obvious reasons. The mass email sending seems to have ceased entirely, but I still cannot change the webpage in my browser from about:blank. I have also observed a program called AlfaCleaner, I've been uninstalling it but it seems to keep reinstalling itself. After my last uninstalling, it hasn't reinstalled yet.

Attached is my HijackThis log.

 

Have decided to just reformat computer per your adivce. Luckily, I don't do any major online buying or banking, will change email and login passwords using this computer. Thanks for your help!