Possible Malware Issue, Need Help - PC stuck in reboot loop

I am trying to figure out whether a PC can be salvaged or not. It has Windows "Embedded" which is somewhat unfamiliar territory for me.

Currently, if you turn the PC on, it shows a screen that says Windows Embedded and some company information (from the vendor that originally supplied the PC.) Then after a few seconds a MSI splash screen appears, which shows the motherboard model number. Then the screen goes black, says no input, and a few seconds later the customized/branded Windows Embedded screen comes back up, etc, it's a loop. It never actually boots Windows as far as I can tell.

I tried pressing different function keys (basically I tried each key one at a time from F1-F12) to try to get a boot menu or into the bios, to see if I could boot from a rescue CD. The only key that worked was f8, which brought me to the menu where you can choose safe mode, safe w/ networking, safe w/ cmd prompt, boot normally, etc. However, any of the safe mode options don't really work, it just quickly drops back to the infinite loop.

Finally I disconnected the sata cable to the hard drive, started the PC, put in the Kaspersky rescue CD, and it booted from the CD (finally.) I re-connected the sata cable and was able to browse to C, D, and E partitions on it (via the Kaspersky O/S or whatever that CD runs) so I know it is detecting the hard drive after I reconnect the SATA cable.

When I do the Kaspersky scan, it fails to find anything however.

I tried again with the Avira rescue disc, same result - it did not find anything.

I tried again with the Comodo rescue disc, and when I get into the scan, it gets to around 25% then the scan suddenly just disappears. If I open it again and start a new scan, it does the same thing - seems to be scanning fine for maybe 3-5 minutes, then suddenly closes the scanner.

Any advice on how to proceed would be greatly appreciated... I have been out of the technical scene for a little while, so I am not entirely current on all the latest scumbagware that's out there unfortunately. And I am not 100% sure, it could be a hardware problem - the vendor claimed it's a virus/malware problem and they can't fix it.

No one?

What is the vendor basing their assessment on? Have they looked at the system? Sounds like the system may be hitting a fault or stop error on boot and then restarts again. Could be some type of file corruption or hard drive issue. Can you boot to a drive diagnostic disc and test the hard drives or run a RAM test using a boot disc?

I don't think this is a virus or malware, it might be a problem with the hard disk itself or perhaps a Windows OS issue that causes it to loop as soon as the OS or Windows drivers start to load. If there is any data on it I would hook up the drive externally elsewhere and pull the data off. Since it is embedded I imagine it is used for a kiosk or perhaps POS? If you have another SATA hard disk laying around you could reload the Windows Embedded and your company specific software if you have the discs to do so.

You could also try hard drive diagnostics off of a bootable CD. You should be able to boot to CD even with the hard disk attached. If it is bootlooping BEFORE you get to boot off the CD it is because the Hard Drive is ABOVE the CD/DVD drive in the boot order. Boot into the BIOS and change the boot order to the DVD drive first.

The vendor is less than useless unfortunately. I can't do a typical restore/repair operation to try to fix boot config because I don't even have a Windows disc for this (again, it's windows embedded - who uses that??)

I can definitely check the manufacturer and model of the hard drive and see if they have a bootable utility disc (pretty sure I remember doing this once years ago with a WD hard drive...)

There are 3rd party hard disc diagnostic tools as well that you can burn an ISO to disc.