Internet connection sharing problems on Windows XP SP2

Hello, this post is about how to fix errors such as:

svchost.exe - Application Error: The instruction at "0x00000000" referenced memory at "0x00000000". The memory could not be "read".
Click OK to terminate the program
or
Click CANCEL to debug the program

I've recently experienced such problem: about 10 minutes after running my computer: the svchost.exe pops up with the above memory access violation i.e.: cannot read from memory OK or Cancel. Whatever button I press on my Internet stops and I have to restart in order to regain functionality or just to ignore the popup.

I've searched for such svchost errors and even updated it but still experienced the problem. Then I grabbed ProcessExplorer (http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx) and pointed with the 'target' tool to the error message. It appeared that the owner of the error was csrss.exe.

Next thing - I went to microsoft.com website and found a critical update to its windows users( http://www.microsoft.com/technet/security/bulletin/MS07-021.mspx). Applied it, but the problem stayed.

This time I looked at the Windows' event log and I saw that the Windows Firewall/Internet Connection Sharing could not be started because of error: 5( access denied ).
After some research here is what I found: http://support.microsoft.com/kb/892199
It appears that upon restart certain permissions prevented you from starting the Windows Firewall service( SharedAccess ) again in Windows XP Service Pack 2. So service's permissions got to be restored:
How: open command prompt: Start->run->cmd and type

SC sdset SharedAccess D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU)

P.S. if you're still experiencing problems try the following:
1) upgrade to SP3
2) disable and stop the Computer Browser and Server services from: Start->Run->services.msc
3) run a scan with a-squared free.

Cheers and I hope it helps you! by Nevyan Neykov

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