Original post by: david chase ,
If you want to keep your OS and data safe then they best way to fix this issue by taking the motherboard backup battery out and put it back using following steps: You need to open the lower black panel apart for this you can follow the online YouTube tutorials. Once panel is taken apart then you will see a small battery cell connected with 2 red and black wires via jack. Take this jack off to disconnect the battery for about 10 mins then put it back and try turning on your pc. This shall reset your BIOS passwords etc and then you would be able to login in to your PC.