My grandson has a Packard

Question

My grandson has a Packard Bell MS Model RNOOO
Model Hype ref: UTOW - REN.

Mum was cleaning the bedroom and moved the computer when it was off. When put back on there is a constant bleeping and the monitor just comes on and says no signal.

Could dust be the problem?? I have checked all the wires and even changed them over with his sisters who has the same system but to no avail.

Help please