Freezing Laptop problems!

Hello,

Whilst I am at home, I remove the battery from my Samsung R540 as not to waste it. The ohter day the AC power cord was accidentally pulled out from my computer, cutting the power and turning off my laptop. After that, I plugged the cord back in and switched the laptop back on. It booted as normal but when it came to the desktop, none of my usual programs opened, and anything I tried to click on would freeze. Ctrl+Alt+Dlt came up with
'Failure to display security and shut down options' so I restarted, waited for a good 30 minutes and everything was still freezing and not responding. I restarted again and again, tried with and without the battery or charger. I ran a Norton virus scan and CHKDISK, both came up with nothing. I did a system restore and cleaned the disk. I would have defragged it too, but the disk defragmenter won't open for some reason.
So now I can only use it in 'Safe Mode' and that is such a pain.
Is the problem caused by a program that was open when the plug came out, or have I damaged something inside the computer? What can I do to fix it?
Any help is appreciated, thank you so much.