First guess, PSU failure. HP/Compaq and many other out of the box computers have very basic (pretty whimpy) power supplies, they do fail. If you are not tech savvy, take it to a shop and have it tested. PSU replacement is not a major job and a basic supply is not that expensive. If it is a supply, the whole job should take no more than 15 minutes.
Any help or suggestions would be greatly appreciated: I have a desktop computer that was working fine the other night but this morning when I tried turning it on, nothing happened. I unplugged everything but the power chord and the monitor- still nothing. I took out the power chord, waited several seconds and then plugged it back in, and when I press the power button it came on for a second the turned off. There is a little green indicator light showing that the system is receiving power.
The computer is a Windows Vista Home and Premium OEMAct. The tower has a Compaq logo, the model number is CQ511OF. It is an older computer I'd guess maybe 7ish years old.
I'm hopeful it might be the power button, but I know it may also be the motherboard.
Thank you for your time