After installing Win8 x64 RC, Metro apps worked correctly, but desktop OpenGL apps were slow and unresponsive. I installed the latest Win8 nVidia drivers, and the OpenGL apps started working correctly. At the same time, because of annoying permission messages, I changed the C:\ drive and all its files ownerships to my user, and gave it full permission.

I restarted my pc after installing the drivers, and now Metro apps only show the splash screen, then crash.

I tried installing other versions of the nVidia drivers, with the same result.

My GPU is a GeForce GTX275.

Is this a known problem with nVidia drivers? Or maybe changing the ownership of C:\ is the real problem?

Thank you.

More information (after looking in the event viewer)

I've managed to find the problem and the error in the Event Viewer. I still cannot solve it. Here's the information I found by opening the Mail app and letting it crash:

Log Name:      Microsoft-Windows-TWinUI/Operational
Source:        Microsoft-Windows-Immersive-Shell
Date:          07/06/2012 15.54.17
Event ID:      5961
Task Category: (5961)
Level:         Error
Keywords:      
User:          VEE-PC\Vittorio
Computer:      vee-pc
Description:
Activation of the app microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail for the Windows.Launch contract failed with error: The app didn't start..
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Immersive-Shell" Guid="{315A8872-923E-4EA2-9889-33CD4754BF64}" />
    <EventID>5961</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>5961</Task>
    <Opcode>0</Opcode>
    <Keywords>0x4000000000000000</Keywords>
    <TimeCreated SystemTime="2012-06-07T13:54:17.472416600Z" />
    <EventRecordID>6524</EventRecordID>
    <Correlation />
    <Execution ProcessID="3008" ThreadID="6756" />
    <Channel>Microsoft-Windows-TWinUI/Operational</Channel>
    <Computer>vee-pc</Computer>
    <Security UserID="S-1-5-21-2753614643-3522538917-4071044258-1001" />
  </System>
  <EventData>
    <Data Name="AppId">microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail</Data>
    <Data Name="ContractId">Windows.Launch</Data>
    <Data Name="ErrorCode">-2144927141</Data>
  </EventData>
</Event>

Found other stuff, this is another error that appears when opening a Metro app:

Log Name:      Application
Source:        ESENT
Date:          07/06/2012 16.01.00
Event ID:      490
Task Category: General
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      vee-pc
Description:
svchost (1376) SRUJet: An attempt to open the file "C:\Windows\system32\SRU\SRU.log" for read / write access failed with system error 5 (0x00000005): "Access is denied. ".  The open file operation will fail with error -1032 (0xfffffbf8).
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="ESENT" />
    <EventID Qualifiers="0">490</EventID>
    <Level>2</Level>
    <Task>1</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2012-06-07T14:01:00.000000000Z" />
    <EventRecordID>11854</EventRecordID>
    <Channel>Application</Channel>
    <Computer>vee-pc</Computer>
    <Security />
  </System>
  <EventData>
    <Data>svchost</Data>
    <Data>1376</Data>
    <Data>SRUJet: </Data>
    <Data>C:\Windows\system32\SRU\SRU.log</Data>
    <Data>-1032 (0xfffffbf8)</Data>
    <Data>5 (0x00000005)</Data>
    <Data>Access is denied. </Data>
  </EventData>
</Event>

After changing permissions again (adding Everyone and Creator Owner to System32), the "access denied to sru.log" error disappears, but this one appears in its place:

Log Name:      Application
Source:        Microsoft-Windows-Immersive-Shell
Date:          07/06/2012 16.16.34
Event ID:      2486
Task Category: (2414)
Level:         Error
Keywords:      (64),Process Lifetime Manager
User:          VEE-PC\Vittorio
Computer:      vee-pc
Description:
App microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail did not launch within its allotted time.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Immersive-Shell" Guid="{315A8872-923E-4EA2-9889-33CD4754BF64}" />
    <EventID>2486</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>2414</Task>
    <Opcode>0</Opcode>
    <Keywords>0x2000000000000042</Keywords>
    <TimeCreated SystemTime="2012-06-07T14:16:34.616499600Z" />
    <EventRecordID>11916</EventRecordID>
    <Correlation />
    <Execution ProcessID="3008" ThreadID="6996" />
    <Channel>Application</Channel>
    <Computer>vee-pc</Computer>
    <Security UserID="S-1-5-21-2753614643-3522538917-4071044258-1001" />
  </System>
  <EventData>
    <Data Name="ApplicationId">microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail</Data>
  </EventData>
</Event>

Now I'm stuck. It tells me "Activation of app microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail failed with error: The app didn't start. See the Microsoft-Windows-TWinUI/Operational log for additional information." but I can't find the Microsoft-Windows-TWinUI/Operational log.

I'm starting a bounty.

I found the TWinUI/Operational log. It only tells me:

Log Name:      Microsoft-Windows-TWinUI/Operational
Source:        Microsoft-Windows-Immersive-Shell
Date:          07/06/2012 16.28.57
Event ID:      5961
Task Category: (5961)
Level:         Error
Keywords:      
User:          VEE-PC\Vittorio
Computer:      vee-pc
Description:
Activation of the app microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail for the Windows.BackgroundTasks contract failed with error: The app didn't start..
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Immersive-Shell" Guid="{315A8872-923E-4EA2-9889-33CD4754BF64}" />
    <EventID>5961</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>5961</Task>
    <Opcode>0</Opcode>
    <Keywords>0x4000000000000000</Keywords>
    <TimeCreated SystemTime="2012-06-07T14:28:57.238140800Z" />
    <EventRecordID>6536</EventRecordID>
    <Correlation />
    <Execution ProcessID="3008" ThreadID="2624" />
    <Channel>Microsoft-Windows-TWinUI/Operational</Channel>
    <Computer>vee-pc</Computer>
    <Security UserID="S-1-5-21-2753614643-3522538917-4071044258-1001" />
  </System>
  <EventData>
    <Data Name="AppId">microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail</Data>
    <Data Name="ContractId">Windows.BackgroundTasks</Data>
    <Data Name="ErrorCode">-2144927141</Data>
  </EventData>
</Event>

I need to go deeper. I found a forum thread that told me to look for "DCOM" errors. I found this one related to the app crash

"The server Microsoft.WindowsLive.Mail.wwa did not register with DCOM within the required timeout."

Log Name:      System
Source:        Microsoft-Windows-DistributedCOM
Date:          07/06/2012 16.46.45
Event ID:      10010
Task Category: None
Level:         Error
Keywords:      Classic
User:          VEE-PC\Vittorio
Computer:      vee-pc
Description:
The server Microsoft.WindowsLive.Mail.wwa did not register with DCOM within the required timeout.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-DistributedCOM" Guid="{1B562E86-B7AA-4131-BADC-B6F3A001407E}" EventSourceName="DCOM" />
    <EventID Qualifiers="0">10010</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8080000000000000</Keywords>
    <TimeCreated SystemTime="2012-06-07T14:46:45.586943800Z" />
    <EventRecordID>2763</EventRecordID>
    <Correlation />
    <Execution ProcessID="804" ThreadID="2364" />
    <Channel>System</Channel>
    <Computer>vee-pc</Computer>
    <Security UserID="S-1-5-21-2753614643-3522538917-4071044258-1001" />
  </System>
  <EventData>
    <Data Name="param1">Microsoft.WindowsLive.Mail.wwa</Data>
  </EventData>
</Event>