I've got a Pentium system that was working fine, I've fiddled about with it and changed a few things so I'm 100% sure what's causing the issue. I can, of course, start replacing items one at a time to get to the bottom of it, but someone here might know something obvious I'm missing.

It was booting of a 1GB HDD with 32MB RAM. I've added another 32MB RAM that was from a working, identical system. It now has 4x 16MB sticks. The mobo supports 64MB RAM.

I've swapped the HDD for an IDE to CF converter and a 1GB CF card. This card already had DOS + Win3.1 and it booted fine, although WIn3.1 froze on the splash screen. I formatted the CF and installed Win98, the setup ran without issue, but then after reboot it failed to start.

The machine finishes POST, then seeks the floppy drive and then stops with nothing on screen apart from a blinking cursor. If I boot from floppy I can boot into DOS, and no doubt reinstall Windows.

So I'm guessing it's possibly something to do with either some advanced way of accessing the HDD or the extra RAM that's causing the issue when Win98 starts to boot, that doesn't happen in DOS. But with no error message, I'm none the wiser. I've tried disabling the advanced HDD options in bios like PIO Mode and 32bit disk access, but it didn't help.

The next step is to remove the RAM and plug the HDD back in, the only problem is this is a proprietary compact desktop and changing the RAM and HDD involves completely stripping down the case and it's a massive pain in the ass!