Boot problem after cleanup

Hello,
After running a system cleanup (PC Doctor) and optimization process, I restarted my computer only to have it fail to boot. It is a custom-built core i7 running windows 7 64 bit. It appears that everything is still starting up inside, so I'm not certain whether I've merely killed the video and audio of the system, or if the problem is deeper. I do recall deleting an AMD file during the cleanup, which would lead me to believe that this is video card related. Any help would be appreciated.