3d games crashing back to desktop

when playing Oblivion the game will run for about 5 mins then crash. And playing rome total war my computer fairly regulary goes to desktop (very similar manner to pressing (alt+tab) but without actually pressing anyting. but i can click the task bar tab and bring it back up with no problems, Oblivion just crashes totally. However The Sims2 has no problems at all?????

 

windows error checking messages

As well as the listed one below, i also recieved... i2c return failed

Event Type: Information
Event Source: ACEEventLogSource
Event Category: None
Event ID: 0
Date: 11/12/2006
Time: 3:33:44 PM
User: N/A
Computer: SIDEW1ND-EGOWQM
Description:
0000000004: 2006-11-12 15:33:44:437 Exception: Object reference not set to an instance of an object.
Exception Called by: ATI.ACE.CLI.Component.Icomponent.Icomponent::Run processID:02216 threadID: (CLIIcomponen) domainName: (cli.exe ) assemblyName: (CLI.Component.Icomponent, Version=1.2.2460.36741, Culture=neutral, PublicKeyToken=90ba9c70f846762e)
*********************************************************************
Event Type: Information
Event Source: ACEEventLogSource
Event Category: None
Event ID: 0
Date: 11/12/2006
Time: 3:33:44 PM
User: N/A
Computer: SIDEW1ND-EGOWQM
Description:
0000000003: 2006-11-12 15:33:44:390 ATI ACE Runtime not found!
Error Called by: ATI.ACE.CLI.Component.Icomponent.Icomponent::ConnectToRuntime processID:02216 threadID: (CLIIcomponent ) domainName: (cli.exe ) assemblyName: (CLI.Component.Icomponent, Version=1.2.2460.36741, Culture=neutral, PublicKeyToken=90ba9c70f846762e)
------------------------------------------------------------------------------------------------------------------------
Event Type: Information
Event Source: ACEEventLogSource
Event Category: None
Event ID: 0
Date: 11/12/2006
Time: 3:33:44 PM
User: N/A
Computer: SIDEW1ND-EGOWQM
Description:
0000000002: 2006-11-12 15:33:44:375 Can't connect to Runtime
Error Called by: ATI.ACE.CLI.Component.Icomponent.Icomponent::ConnectToRuntime processID:02216 threadID: (CLIIcomponent ) domainName: (cli.exe ) assemblyName: (CLI.Component.Icomponent, Version=1.2.2460.36741, Culture=neutral, PublicKeyToken=90ba9c70f846762e)
------------------------------------------------------------------------------------------------------------------------
Event Type: Information
Event Source: ACEEventLogSource
Event Category: None
Event ID: 0
Date: 11/12/2006
Time: 3:33:44 PM
User: N/A
Computer: SIDEW1ND-EGOWQM
Description:
0000000001: 2006-11-12 15:33:43:453 Exception <Runtime@2392>: No connection could be made because the target machine actively refused it
Exception Called by: ATI.ACE.LOG.Foundation.Service.Service::ConnectToObjectImpl processID:02216 threadID: (CLIIcomponent ) domainName: (cli.exe ) assemblyName: (LOG.Foundation.Service, Version=1.2.2460.36737, Culture=neutral, PublicKeyToken=90ba9c70f846762e)
************************************************************************************************************************
Event Type: Information
Event Source: ACEEventLogSource
Event Category: None
Event ID: 0
Date: 11/1/2006
Time: 4:49:15 PM
User: N/A
Computer: SIDEW1ND-EGOWQM
Description:
0000000001: 2006-11-01 16:49:15:187 null _aspectName
Error Called by: ATI.ACE.CLI.Component.Dashboard.DashboardForm::_aspectNameExists processID:01568 threadID: (CLIDashboard ) domainName: (Cli.EXE ) assemblyName: (CLI.Component.Dashboard, Version=1.2.2460.36742, Culture=neutral, PublicKeyToken=90ba9c70f846762e)
------------------------------------------------------------------------------------------------------------------------
Event Type: Information
Event Source: ACEEventLogSource
Event Category: None
Event ID: 0
Date: 10/28/2006
Time: 5:17:41 PM
User: N/A
Computer: SIDEW1ND-EGOWQM
Description:
0000000001: 2006-10-28 16:17:41:281 Exception: An existing connection was forcibly closed by the remote host
Exception Called by: ATI.ACE.CLI.Component.Systemtray.Systemtray::Run processID:04092 threadID: (CLISystemtray ) domainName: (cli.exe ) assemblyName: (CLI.Component.Systemtray, Version=1.2.2425.37164, Culture=neutral, PublicKeyToken=90ba9c70f846762e)
************************************************************************************************************************