Hi Guy's.....I'm back! After many hours reading and re-reading the excellent toot's that were recommended and applying them .I think I have finally solved it!!
I will try to keep it as short as possible......First off I checked all the aircraft folders in FS9.....guess what?...I found three aircraft neatly tucked up in the Beech Baron folded.....I checked the BB cfg folder and it only showed the information for Beech Baron so that meant that I could get rid of the offending aircraft....in doing so I lost the BB

.....No problem.... uninstalled the Sim and reloaded it....Problem solved!
Next thing to do was to apply the advice that you guy's gave me(I have learnt quite a lot of basic computor'skills' in doing it.....Manuals always seem to assume that everyone who buys a computor knows how they work

)
I tried the cut and paste but found that it only put the aircraft in the FS9 Aircraft folder,it didn't show up in the Sim,Soooo! I tried the 'lift an drop' method'(HOW to's Aircraft Installation.....same aircraft as previous attempt) That worked fine .... the aircraft appeared in the FS9/aircraft folder and in the Sim.Having solved the problem of getting a successful download I then applied that to other downloads......The success rate is about 50%(See SIBBRITT's comments in his post on Feb 20) so I am not too bothered about that ,at least if the download is compatable then it will show up!
Thanks to HAGAR,FRANK_CARBON,MattNW and the other's that I haven't mentioned.
In future I will have try to remember the principles that I applied when I worked for a living

(Development Engineer in R&D in the Aircraft and Medical industry) ....only try ONE thing at a time ,....if that dosen't work put it back to square one and try something else!!!......... the two 'brain cells' are what I have got left now!!

....I devide my time now between Computors and 'HAM Radio' ....Hence the G7
Thanks Guy's