Re: Dell Studio XPS 435MT won't start with a CMOS Battery
5 beeps is "real time clock failure" and the solution is supposed to be a new motherboard battery. Sure the replacement battery is good?
When yu replaced the battery, did you: power off, unplug and press/hold power button for ~15 sec, then remove the battery and press/hold power button again for ~30 sec, and finally install the new battery ?
You might also want to reseat all the RAM modules and PCI cards in their slots, though this may not help.
If all that fails, it might be a motherboard failure which is preventing it from detecting the battery voltage...