[Kalim]

Run whats advised above: HDD Diagnostic Tools

If you ever change the battery, make sure you get all the BIOS info jotted down so you know what to change it back to.

 

[Kalim]

Before you moved your battery you should have noted all your settings of the BIOS. Now you'll have to return them to previous working ones.

Can you hear your system and CPU fans moving when you start the system?

Open the side of the case to visually look if the fans are spinning. Make sure putting the battery is in properly.