I have an old SCO-UNIX machine which I support a long standing client / friend with.
I don't use it very often, and is kept switched off. All was well 2 weeks ago, but when I tried to boot today all I get is a continuous set of long beeps but no booting. I have checked inside and cant see any obvious signs of a problem.
In my experience most "long beeps" are generated by the hardware's BIOS and indicate memory problems. I would recommend you re-seat all the RAM memory first (in case of a simple poor connection between the memory module and the motherboard), followed by selected removal and testing of a subset of memory modules until the beeps cease. Of course, I could be completely wrong.