XP Media Center won't boot normally but does boot safe mode

[sb2]

My HP media center running XP Media Center sp2 (nearly the same as xp pro)was working well, then one day stopped booting. I can get the machine to boot using safe mode with networking and then tried msconfig and selected Diagnostic Startup to get a clean start. This still won't boot properly. Any ideas on how I can determine what the problem is? (I have run chkdsk, and it found an area that it repaired, but I don't know where that was.)

 

[sb2]

Note in Safe Mode I tried to run sfc /scannow but it would not run because the RPC server was not available. tried to run sfc /scanonce, but I don't think iti is working either.