Area-51 R2, CMOS battery fail

Hello

On startup I get a CMOS battery fail but after an auto reboot it was ok aside from the date/time needing adjusted.

However lately I've noticed it lockup after use where no input devices seem to work.

Do I just need to replace the battery to resolve this?

If so what type of battery is required for Alienware Area-51 R2?

Thanks for your help.

Darren