Shoutbox

hi all,
i have had been having troubles with my computer since about a fortnight.
well to start off with, one day, i woke up in the morning and turned on my computer, but the monitor would not start and the LED on the monitor just blinked on and off. i checked my CPU for all connections and found everthing fine. so i bought a new battery for the computer and replaced it with a new one (the circular battery) and the computer started running fine but all the BIOS settings had been reset, so i had to adjust it again.
now, about 4 days back, the same problem started again, so i again bought and replaced the battery, thinking i might have got a defected one. but since then, every time i start my computer, all BIOS settings get reset and it doesnt detect my hard-drive or CD-ROM, only floppy drive. i have to restart it several times before it reads my HD. also, it takes a very long time to boot, its stuck for 3-4 minutes on a black screen with an _ flickering.
i have an Intel GAV915 Motherboard, 1 GB of RAM, 1 samsung 40 GB Hard-drive.
please help me repair this.
thanks
edit: Please Help Me..