Is the BIOS set to boot from the hard disk first? In that case, connecting a RJ45 cable (to your modem or router?) shouldn't make any difference, even with that modem or router turned on (you didn't tell if turning it off or on makes any difference).
Assuming that "not getting start" means it doesn't start at all, this is not a Windows problem, since Windows only becomes active later. So it's either a setting in the BIOS (did you try the defaults?) or a hardware issue with the motherboard.
Kees
My english is not good sorry for the mistakes.
When i put on the CPU it ll not getting start but when i remove rj45 connector from CPU, it gets start. Each time i have to do the same. How to recover the problem?

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