You bought it in the up position, then let it down, and can't get it up now (and haven't been able to get it up at all)? Right?
With the unit sitting there for 10 years, it's likely to have dry seals and a hydraulic fluid leak. Does you have the owner's manual? If not, here's a link to one:
http://www.hilotrailerforum.com/f49/...o-models-3467/
See page 7 & 8 for lift mechanism troubleshooting.
Check hydraulic fluid, likely the major problem.
You say "loose pully system". Are the pulleys loose, or the cables? The pulleys should be very stable and the cables should be taut. Will likely require adjusting, also in the owner's manual. May need replacing. How about the cable attachment to the top half of the trailer? They might be a bit loose at that connection.
Are the guide blocks intact? You are probably already working on the bent safety bar and the broken safety wire.
Looks like you have a project on your hands!! Keep on it and you'll have a jewel when you finish!!
Good luck