When the dead teacher is found she has a gag in her mouth. In 1 or 2 shots that gag is clearly missing.
After the death of Xander, the police disconnect and seize Amy's computer as she complains she needs it for work. During the entire scene, a Steam window remains visible on her TV, clearly indicating a PC is still running. She then leaves for a gaming cafe as she says she needs to continue working, indicating that the PC being seized is the only one she has. Steam, obviously, requires a PC.