Chandler's Dad, rotorcraig and Tinstaffl
Many thanks one and all.
The beep codes, unfortunately, can't help now, as rotorcraig points out.

In
fact, the last heard beep series were three LONG beeps!!!! ) can't find THAT sequence in any of my bios books.

Now for the latest in this thrilling saga ...
Decided that the only answer was to buy another base system (secondhand, 'cos I'm a cheapskate!); found one on EBay, case, mobo, AMD processor, 1Gig RAM, 80 Gig HD, DVD and separate CD drives, plus O/B display and multi USB and Firewire ports. Cracking!!!
Until, that is, boot-up is attempted. Constant messages 'searching for Boot Record from Floppy' then from DVD/CD drives then from IDE 0' - 'Not Found'
Tried eight different HDs and eventually found one which gave 'IDE 0 - OK.
HOWEVER, it asked for a restart and launched itself into another search for boot records followed by 'UNDI, PXE-2.0 (build 082) - OK
INTEL UNDI, PXE 2.0 (build 082)
Copyright (c) 1997 - 2000 Intel Corporation
SIS 900 PXE BootRom V 1.07 Hook Int 19
Client MAC ADDR: 00 06 6A 89 69 D5
GUID: FFFFFFFF - FFFF - FFFF - FFFF - FFFFFFFF
PXE -E51: No DHCP or Proxy DHCP
PXE-M0F: exiting Intel PXE ROM
then Searching for Boot Record from Floppy etc., etc., etc.,
My head hurts and I don't understand any of that. Is there any kind soul who could interpret - either the significance of the hex addresses and/or the reference to PXE ROM or. indeed, Intel on an AMD mobo
Exits left, mumbling and weeping copiously.