elite 7300 won't boot anymore

hello,

i'm having problems with my elite 7300 pc, as described here:

http://h30434.www3.hp.com/t5/Desktop-Lockups-Freezes-Hangs/elite-7300-won-t-boot-anymore/m-p/4469332

in short, i rebooted and now i'm stuck at the blue hp boot screen (press esc..).

no hardware changes, no prior issues.

it's out of warranty, any suggestions on how to fix it?

thanks & regards,

yxyxx