Stop error: C000021a Need help and or advice

Ive been attempting to resolve my problems with my xps for quite some time now. I know I should probably just take it somewhere to get fixed by a professional. But now since I have so much time invested id rather learn how to fix it myself just in case I run into similar problems in the future. Okay here is a little background information of how this all started. The power went out in my home and the computer was on. When I restarted it I got the BSOD and it told me The computer was shut down to protect the computer from a serious error due to power failure (I cant remember exactly, this happend 3 months ago). Then it gave me the option to start windows normal, last known good configuration point, safe mode. For a little while by choosing last known good configuration the computer would work for about 45 mins then I would get the BSOD again. Soon after I got "Un mountable boot voulme error" My friend ran the diagnostic utility and diagnosed it as a bad hard drive. So I replaced the hard drive with a seagate sata 300 gb. My old hard drive is a samsung 160 gb 7200 rpm. Hopefully this will help. Finally after figuring out my dvd drive no longer read disks (I replaced with a new dvd drive) I was able to boot from my dell oem OS dvd. After windows installed it began to install applications. Soon after I received a stop error. Stop: 0x0000007E (0Xc0000005, 0x805BFA8F, 0XF7A74424, 0xF7A74120). After attempting to access the recovery console from the OEM OS dvd I received another stop error. Stop:C000021a {Fatal System Error} The windows logon process system process terminated unexpectedly with a status of 0X00000407 (0X00000000, 0x00000000) The system has been shut down. I reinstalled The OS from the dell dvd, reset my admin password. So now im able to access the recovery console. I typed in the chkdsk /r command. Is it even possible to repair the stop error C000021a using the recovery console?? THANKS IN ADVANCE for any help and advice offered!! I just want my computer back. This is so frustrating. Its going on 4 months now since this all began. Im glad we have two other computers in the house.