Windows 7 Can't Get Past Login Screen

Hello, I was hoping someone here could help me with a problem I encountered earlier this afternoon, since I couldn't seem to find this particular issue anywhere after about an hour of Googling.After rebooting my computer, I found myself unable to get past the login screen. Windows boots normally, it doesn't hang or freeze...it takes me to the login screen as expected, and I type my password in as usual. It accepts this without error, so I know my password isn't wrong or anything like that...but after displaying the 'welcome' message and loading circle for a few seconds, the screen flashes black, and bounces me right back to the login screen. It doesn't reboot my computer, I don't get stuck at the Windows logo or anything like that...it's just not taking me to my desktop after I log in, no matter how many times I try or reboot. Fortunately, I've got a Linux partition, and worst case scenario I can still access all my files and back them up should I need to do a clean install...but I'm sure there's a way to fix this.Before rebooting, I had changed my visual style, something I've done in the past. I'm guessing that the issue is with one of the system files that got replaced - explorerframe.dll or shell32.dll, for instance (the tool I use is Windows Themes Installer by Kishan-Bagaria). I've never had issues with changing visual styles before, but obviously this is the most likely cause for the sudden issue. Is there a way I can restore the files to their default states? Any help would be appreciated, thanks.