I have a Hp pavilion and recently got the blue screen of death when i try to factory reset it just fails. I dont have the boot disc anymore. Any way to reset or startup through cmd? or do i have to flashdrive boot?

Download and run blue screen viewer from nirsoft
Post screen shots of each error.

You'll need a Windows cd or thumb drive and your license key to format.
Thoughts if it's hardware a format won't help so the info above could help us with that.

Depends what's causing the blue screen; ould be hardware or software failure. Can you at least get into bios?

0xc00021a

thanks
I lost my installation disc so I am about to buy a key from ebay and download to a flash drive.

Will this key work? https://www.***com/itm/Windows-8-1-Pro-Professional-32-64bit-Product-Activation-Key-Multi-Language/292497297669?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20140131123730%26meid%3D7f30f4c313da42d5a9a7f77b24678420%26pid%3D100167%26rk%3D6%26rkt%3D15%26mehot%3Dpp%26sd%3D123083209570%26itm%3D292497297669&_trksid=p5411.c100167.m2940

Yes but I would seriously opt for "Windows 10 64bit Pro" these days.
Also careful with those links, Prime example why.

http://forums.d2jsp.org/topic.php?t=73472775&f=34&p=496626976#p496626976

Cool thanks i found an win8 for $3 plus its my old computer so as long as it works it will be good enough for what it does.

I mean its maybe a dollar difference if that in price.
but go with w/e OS you prefer.