OP I have no idea what PC you have?
for sure all things inside, PSU model full # (tag makers name and model #)
all cables connected, or failed to connect.?? AUX?
no PCI slot filled,? with what? Video card If yes what card?
We get it the HDD has windows and is no good
and you try to install windows, from unstated media,
we can not ever guess what media or if ISO from whom?
stop searching on google , otherS PC are not Your PC, ok?
learn to post facts full please.
or post photos of all you have there.
there is no other way to get help with everyone here blind in a text box. or googling, all helpers are blinded by lack of key facts.
first off its not new, but is new to you ,my guess bought used off fleabay for way too much cash, as we see endless now.
the 870 is the oldest I7 ever made, GEN 0 it 1870 is gen1 so
we are up to gen 9 now. so old old cpu it is but not a problem
for w7 (w10 is a problem ask)
G0 is ok, just slow, no issues. Intel built September 2009
as you can see it is 9 years old today. NOT NEW.
1: no install media stated.
2: PSU model not stated.
3: power cables to mobo (both) and to GPU card AUX not stated.
4: DDR3 memory partnumbers and maker not stated, matters.
DDR3 must be on Acers qualified memory list, is it? I cant look for you, unless told make and model ram.
My guess is wrong PSU, I cant see your PSU or inside your case but let me guess the MOBO 4 pin aux cable is MISSING.
and that will fail. just like you said.
the BIOS 1 page, set BIOS to defaults and exit save.
and if you did that the HDD0 will boot, if HDD is not defective.
I see you installed w7 but how far did you get, to the last step reboot? and then it fails ,first removing the w7 unstated media,
(dvd media) not removed the install loops endlessly.
the 2nd phase of the install , runs from HDD only.
and connected to the internet via Ethernet makes that way better. now. plug and play working better like that.
I never install any OS ever, unless I run the HDD tests called
SMART< I run that and if smart fails the HDD IS NO GOOD.
no HDD stated at all, new, or 10 years old, nothing.
Your motherboard, has 2 power feed connectors
24 and 4
I bet 4 pin is missing, cable. am I right,?
If only you';d spec out what is in the box (chassis) or one photo of inside, answers go 10x better, be like the first ever here to do that.
see this wire, here,
from PSU to the far right corner. behind the fan left rear edge
that is AUX if missing the PC crashes all the time or is dead.
if PSU is 1999 to 2008 expect bad caps, we dump these PSU .