Re: Failed Bios flash on dc7900....HELP

I purchased a furbished HP DC7900 E8400 SFF recently.  After update the bios from

http://h20565.www2.hp.com/portal/site/hpsc/template.PAGE/public/psi/swdDetails/?sp4ts.oid=3785038&spf_p.tpst=swdMain&spf_p.prp_swdMain=wsrp-navigationalState%3Didx%253D0%257CswItem%253Dvc_79813_1%257CswEnvOID%253D%257CitemLocale%253D%257CswLang%253D%257Cmode%253D3%257Caction%253DdriverDocument&javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetoken

to 1.23 ver, the PC won't boot (Yes, I did it from Windows - a big mistake).  I tried to create bootable CD (and DVD), and bootable flash drive.  None of them work.  

As now after powering  up, I can only see the HP invent logo.

Would anyone have any suggestion?   Thanks.