When viewing the 4th screenshot at this auction link, what are some of your opinions as to the possible things wrong with this system... Obviously it is likely a bad disk drive, but I thought that perhaps something else may also cause this on screen error message....
link is: https://www.ebay.com/itm/325162751429
and again it is screenshot #4
or the item # for this is:
155028353618
The seller doesn't say there is a disk in the drive, so the check drive message is normal if nothing is there. As to the random characters, my guess would be some bad RAM.
What Nick3092 said.
There is bad RAM that needs to be replaced - that part is simple enough, and the "check disk drive" message is simply because there is no diskette present (or the drive can't read it, but I'm betting the former).
Make him an offer for $100 and see what happens.