error loading SCO unix 5.0.5 in new install

Put Bios in safe mode.

Also, It sounds like maybe your disk is too big for 5.0.5 to deal with.

http://www.tek-tips.com/viewthread.cfm?qid=719546

You can put in boot parameters to specify the disk size, but there is a limit.

There is also the possibility that the install is looking at the MBR for clues.

http://lists.celestial.com/pipermail/sco-misc/2004-March/000511.html

This option should be fine since it's a "blank" drive - some of these are not really blank though.

Also - what hardware?  If it's too modern I doubt it will ever work with 5.0.5.

The hardware is about 15 years old working currently with SCO 5.0.5 but our hard drive is giving badblock errors. so we bought another 4GB scsi hard drive to replace current drive.
I am now getting errors "invalid partion" on boot up of floppy or cd Is that referring to the new hard drive?

Looks like your SCO kernel (or boot driver) is limited to 256MB of RAM

Try at the boot: prompt:

defbootstr mem=0k-639k,1m-64960k


Also:
https://www.experts-exchange.com/questions/21637346/Trouble-installing-SCO-OpenServer-5-0-5-Need-help-BADLY.html

after loading you would need:

SLS oss610b: E820 Memory Sizing Boot Patch

http://www.sco.com/support/ftplists/osr5list.html

Sorry for the Delay in replying. The original computer just died and we replaced it with a Dell GX1 my old hard drive boots fine minus a few bad blocks. We are trying to replace the hard drive with the same Specs also 4gb We downloaded the driver from the internet for the SCSi card 2940uw we get as far entering our license number and code no error message but it dies at that point. starts to load and says please wait.

I can only suggest contacting xinuos.

Have you tried at the boot prompt:

defbootstr mem=0k-639k,1m-64960k

(and setting date back to before Y2K)

What does setting the date back do? I think we tried both way with the date in the Bios
I didn't try "defbootstr mem=0k-639k,1m-64960k ".
Does having a dos partition of 4gb on the drive have anything to do with my problem with the OS not loading.
I will not be able to try or do anything for at least another week.

That bootstring is to get past the known memory issue.  Setting the date back can help with other issues but should not be needed.

After a good load you'd apply this to fix it for good:
http://www.sco.com/support/ftplists/osr5list.html

Took off the Dos partition and then it loaded with no problem