Acer Aspire 4730z hdd failure

[teban]

hi everybody,im new here.I wonder if enyone can help about my laptop probem.i have this Acer Aspire 4730z/vista OS. Since my hdd soon ganna crush,i bought a new HDD for upgrade(toshiba 320) and change the OS at the same time from Visat to Window 7 home premium.
The problem is it doesnt recognized the new Hdd(toshiba 320)that i bought,i also try western digial HDD my spare,but still the unit doesnt ditect the hdd.but when i put back the origal HDD(hitachi 250) of Acer Aspire 4730z, it can detect the HDD. Why is that? What should i do?pls pls pls pls need help......

 

[theog]

Will the Hd's show in BIOS?

 

[teban]

nope,but the original HDD(hitachi 250gig) of the unit(acer asphire 4730z) does show in the bios. Why is that?