My sister's computer failed to start and just stayed in the POST procedures. It messaged us by sounding: a single short beep, a long pause, (repeat forever). So, after learning her system was around 12 years old, we went and bought a battery for the CMOS; brought it home, installed it, and the beeping continued once the power cable was connected and the power button pressed. Next, I learned that endless beeping on her Award bios meant there was a RAM issue. So reseated each piece of RAM and now there is only one beep, which means that POST completed its check successfully, at least that's what I learned, and then the monitor never gets a signal.
The harddisk sounds activity, all the fans work, and I reattached the cables to the harddisk and CDROM drive. Her monitor works because we checked her computer with my working monitor and still no signal. We let her system sit there for about 2 hours now and it's the same.
Thank you so much for reading through this problem I'm unable to solve; hopefully with your help it can be solved.