Can't Flash ROMs

[Sorrows]

Hey guys, I was wondering if you all could help me with an issue I've been having lately.

For some reason, I can't flash any ROMs. When I do, it hangs and hangs and hangs on the Splash Screen. It hasn't always been this way, everything worked just fine until last month I flashed MIUI. It worked, but after I decided I didn't like it, I couldn't flash any new ROM, and none of my backups worked until I wiped data and what not.

I've reformated my SD card, and I still can't flash any new ROMs. Help?