thats because the problem was not just the CMOS battery, kahit pa sira ang CMOS battery, you should still be able to boot. it will give a warning that the CMOS settings are wrong, press F1/F2 (or whatever button) to continue, but you should still be able to boot
check the boot list baka nabago, make sure na una madetect ang hard drive mo (dun mo rin makikita kung nadedetect pa ba ang hard drive. my guess is hindi nadetect ang hard drive. which could be a problem with the cable (try another cable), the hard drive (try another boot device like USB flash drive), the jumper settings (since IDE pa yan), the slot being used (lipat sa kabila and see if the problem persists), or the motherboard itself (kailangan na palitan ang mobo)
have you tried the option to load the default settings?