Hi Bob, welcome to bc.
Right click my computer, select properties.
Click the advanced tab then click the "settings" button under "startup and recovery".
Under "system failure", deselect "automatically restart" and select "write an event to system log" then click ok. Stick in a cd. Got an error message now? If so, please post it. Your system bios is probably set to boot from cd first. When you insert a cd, your system is crashing without leaving an error message. When it restarts, it's trying to boot from your cd first.
Let us know.