lhapke :
The computer screen when I start up displays videos of kittens and people dancing. I cannot delete or open the pc. Even when I turn off the computer, the videos keep coming.
Boot into safe mode (Press F8 after splash screen appears) & logon with your user id.
A few things to do.
Right click your hard drive & do a disk cleanup.
Run your Antivirus scan.
Open your browser & look for suspicious add-ons & delete.
Windows system restore to date prior to the popups occuring.