Pc wont turn off when i hold the button, monitor says no signal

Hello, i recently had a malware scan for my pc and the pc reset and now the pc its self wont turn off when i hold thenpower button and the monitor just shows up with a black screen.
My keyboard doesnt work but my mouse does.
Iv'e tried unplugging the pc and monitor and have put in my reset disc but nothing seems to appear on the screen.
Any help would be appreciated.