The fine folks above have provided you with most of the info you will need. Kerry had one thing very correct; "It's almost always the accumulators"!
Your system being dry though requires a different course of action initially.
You can use hydraulic fluid from Northern Tools or from Tractor Supply to diagnose and test your system, then install the Mercedes/Febi fluid when you have it all lined out.
I imagine your high pressure hose has ruptured. All 3 of mine have done that. But you need to fill the reservoir and see what happens basically. I've also had a pump leak from in between the two halves. No hydraulic fluid in engine, no engine oil in hydraulic system. {not sure how that would even happen really}
So, get some less expensive hydraulic fluid and see what happens. Then the counter-punching can begin. Most items are super expensive new, but are usually available here on the forum or from ebay for much much much cheaper. Accumulators
should be purchased new!! Only real "wear" item. And on the hydraulic line, some folks like to replace the hose themselves re-using the brass end pieces, but for not much more $$$ I have taken all of mine to a hydraulic hose repair place and is was in the $60-$65 dollar range to redo.
So, in summation, fill it, and see what happens......