"Fisrt I changed it with a new one and then forced all drives to ONLINE." This is worse.  Instead of 99% of the data on the disks matching and there only being partial/moderate data loss, 0% of the data matches, virtually guaranteeing moderate/full data loss. "In between more and more drives went OFFLINE as I pulled wrong cables. I also did tried to import foreign config (inside the windows graphical UI) but all found foreign configs where the same" In the case that you pulled more than one disk, creating multiple foreign configs, none of which being complete enough to complete the RAID array, then the proper course would have been to retag the array (delete, recreate array without initializing). At this point, none of these things are going to work though.
Please give me some advice before my wife kills me and my kids ask her what happened to dad....  I have a perc 5/i adapter with 7 HDDs (2TB each) on it configured as 1 array RAID5. Suddenly one drive failed, I could hear that awful sound from the drive needle. I am on a win7-x64 machine. Dell SAS Raid Storage Manager v.2.67.00 told me RAID was degraded and I had to make offline the specific drive so I could change it later. That's what I did. But trying to figure out which one was the failed one I pulled the wrong cable. I took out the wrong drive. Then, I pulled more wrong drives, until I found the failed one and changed it with a new drive. now gosh!, RAID was degraded. I saw several foreign configs, I then changed everything to On line state, physical initialization of the new drive took place  and then RAID is OK again. Except my files aren't there. 9TB of family data is lost!!!! I tried "check consistency" it produced some errors in the start but continued to 100%. It took about 20 hours to finish My files still not there. I am afraid to start a new initialization of RAID, firstly it takes 5 days, secondly it could destroy the data lying in there
Perc 5i Drive change