Packard Bell like to hide things rather well but I think that I've found the manual you're seeking.
Here's how my detective work went:
Starting from Hc4361's link, and using 'Select my product from a list', I found that selecting 'Desktop'and then 'iMedia' led to lots of model numbers that looked nothing like 'S2185', so I took a look at Packard Bell's page about your computer here:
http://www.packardbell.co.uk/pb/en/GB/content/model/DT.U80EK.007
That shows (both within the actual page and in its URL) that 'U80' is a key part of the description, so I looked for that in the list that I'd first encountered. Alas, I could find nothing.
Undaunted though, I tried entering 'u80' in the 'Search by product model' box. That offers just one possibility and clicking on it seems to go to the correct model. All that's then needed is to select either 'Windows 8' or 'Windows 8.1', as appropriate, and then to click on 'Documents', revealing links to the user manuals.
So start by putting 'u80' in the 'Search by product model' box and you're well on you're way to what you're seeking.
Easy, really ;-)