A user, Peter, has just finished upgrading his computer with a wireless keyboard/mouse combination, additional memory, installed new speakers, and replaced his 15 inch flat screen with a 24 inch flat screen. When he boots the computer it immediately starts making a loud beeping noise and will go no further in the boot process. Which of Peters system upgrades is the cause of the problem?
A. The DVI cable is not properly seated
B. Speakers are not properly connected
C. Battery low on wireless mouse
D. Memory is mismatched