Issues with my Dell Inspiron 15

So, my BIOS sees the hard drive just fine, but for some reason, the Windows installer won't even kick off! I tried making a bootable USB, messed around with the SATA settings—switching from AHCI to compatibility mode and everything—but nothing works. I even pulled the battery to try a reset, but still nothing. Zilch.

It actually worked once, briefly! It recognized the drive, but then the installation just died. I saw it create a tiny 100MB primary partition, but it didn't even touch the rest of the 500GB space before throwing some random error saying it couldn't install Windows. Honestly, I have no clue what's going on anymore.

Anyone got any tips? Please help me out!
Thanks!

The most important thing is knowing exactly which error code you're seeing while trying to install Windows.

Ugh, getting this error saying I can't split the partition and it won't let me delete them either
Error 0x80070002 is driving me crazy! Can't delete the partition and definitely can't create a new one

maybe try grabbing the Windows 7 installer and using its setup to wipe the drive

The real issue is you've been messing around in the BIOS, and if you changed something you shouldn't have...

That laptop came with Windows pre-installed along with a recovery partition on the drive that was likely protected somehow, so now we have to figure out what's actually left of it.

First thing's first: check if the date and time in your BIOS are actually correct. Sometimes that error pops up just because the date is wrong... If that's not it, try booting from the recovery partition, assuming it isn't totally trashed...