What causes this message? After my computer has been on for several hours I get the message "Insufficient System Resources for requested service", it works find after I reboot, but it continues to happen over and over again.

Thanks in advance

Post your specs, operating system, AV, Firewall etc & an error number if possible.

Check your Event Viewer via Administrative Tools.

Open the System as well as Application tabs and look for red X errors that coincide with your problem. Details here:

http://support.microsoft.com/kb/308427