I have an AMD Athlon XP machine. The computer was not maintaining time nowadays, but I never bothered to look into it. I switched off my comp day be fore yesterday and when I tried to boot it yesterday, the red light on the CPU turned on , but the green light on the monitor just kept flashing but did not turn on. I tried my CPU with another monitor, but the same problem persisted. I thought it could be a CMOS battery failure since my computer had constantly been loosing time. So, I replaced the CMOS battery. After this, I got a message saying the BIOS settings have been set to default. After this, I logged into windows and left the system on thinking that it could help the CMOS battery to charge up since it was a new one. I went out for 5 mins and by the time I came back the monitor was again blank and the green LED was blinking periodically. I replaced the RAM but to no use...What could be the problem???

Does the computer make any of the regular beeps when you try to boot it?

So you were able to totally get the computer booted and every thing looked fine after you replaced teh battery? Have you tried flashing your BIOS?