Is my computer in standby mode?
Make sure you have the cable that plugs into the back of the computer from the monitor screwed in tight. Also make sure the cable on the back of the monitor is screwed in tight and also that the power cord on the back of the monitor is pushed in all the way.
I'm almost certain you're not in standby mode. Does the computer stay on when you get the no signal message? Do you hear the fan blowing, do you hear the disk drive spinning? If not, I think your system has completely shut down. I'm thinking maybe a virus or some hardware/software conflict is stopping it from completing the boot cycle.
Try getting into the Bios or System Setup to see if the LCD Stays on and the computer stays on. Turn the computer off, then hit the power button to turn it back on. Look at the lcd screen and it will tell you what key to hit to go into the Bios or System Setup. Go into it and let the computer sit for 10 minutes or so to see if it shuts itself off.
If you are successful with the computer staying in the Bios or System Setup lets try getting into Safe Mode and see what happens. Turn the computer off and hit the power button to turn it back on and immediately start hitting the F8 key repeatedly until you see the SAFE MODE option. Select the Safe Mode option and let the system boot up. Safe mode will look different to you. The icons will be bigger and the lcd screen darker, but that's normal. If you are able to see the desktop in safe mode just try opening up MS Word and maybe let it sit for a few minutes to see if it shuts off.
If safe mode was successful, then try booting it normally. If it fails, we know we've got an issue.