My PC restarts- a very Typical case

When I start my Pc it restarts after the Please wait screen with Windows is Starting msg.
However Pc starts in safe mode but I cannot install/uninstall any driver. Also the System & Security log files r corrupted.What to Do? The VGA card and Lan card(built in) r OK. There is no H/w problem since this PC starts with the HDD of similar PC.
MZR Siddiquee