HELP PLEASE

I have downloaded the upgrade from MC 2.8 to MC 3.0.

I have uninstalled the previous version 2.8, edl manager, media log, sentinel... and installed MC 3.0 software. Afterthat I have restarted

The PC doesn't start anymore and give me this error:

stop:C0000218 (registry file failure) \systemroot\system32\config\security

I can only work in safe mode. If I make a previous point restore the PC starts again.

Reinstalling MC 2.8 the PC starts normally, Avid works fine and the system seems steady without any problem.

I've tried 2 times to uninstall MC 2.8 and reinstalling MC 3.0. Same problem !!!!

Already tested the hardware. All it's ok

What the matter with MC 3.0 !!!

I'm out of ideas. I don't want to format and reinstall the operating  system. It has no sense. With MC 2.8 everything works fine...

Someone can give me an help???

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Media Composer 2.8 w/Mojo SDI, HP XW8400,Dual Core Xeon 2.6 0 GHz, 3GB RAM, Nvidia Quadro FX1500, 2 tera internal SATA media drives + Windows XP PRO SP2

"I don't want to format and reinstall the operating  system. It has no sense."

Absolutely wrong.  The "best" way to install v3.0, on Mac or PC, is to do a fresh install of the OS.  With your symptoms, that'd be the first thing I'd do.  I've been doing this a loooong time.  Trust me, you'll spend less time reloading the OS than tinkering with it to get it fixed.

 I completly agree with Randall when i  upgraded i just went out and got a new os drive 120 gig 45 bucks  and reinstalled windows and avid mc 3.0 and all is working great  no problems at all  just edit edit edit make money make money 

 So... It seems I have no other choices...

"It seems I have no other choices... "

That would be the "glass half empty" version.  In reality, you have many choices, but the "best" choice will (probably) be to do a clean install.  C'mon, it'll be fun ...and we're all here to help you through it. 

What appears to have happened in this case is that when Windows updated the registry as part of the Avid install process the registry became corrupted.  The most usual causes of this happening are disc write errors or memory corruption.  Either way, the safest and most reliable approach to fixing it would be to reformat your boot disc and reinstall Windows.  Then replace the programs that you need (including Avid).

You shouldn't feel that MC3 can't be installed on your system.  It is the least likely cause of the problem that you're having.