Hi All, I have a 2011 17” MBP which is running Mavericks 10.9.5 & late last year I upgraded the stock 750GB HDD to a new 2TB one which I partitioned as 2 x 1TB Drives naming them as Macintosh HD1 & Mackintosh HD 2. I have also replaced the DVD Drive with another HDD naming that as Macintosh HD 3. I am having major problems with a stags.bluekai.com pop up that always appears despite my installing Avast Anti-Virus that was supposed to deal with this issue. Even though a new HDD has been fitted, I am still experiencing a bunch of spinning beach balls & other issues which seem affect operation & performance is sluggish & slow. I have done Etrecheck, Malware Bytes & run repair permissions & repair disk and all seem fine there. Avast anti-virus has not flagged up any issues. Macintosh HD1 which is acting as the normal start up drive is less than half full. I am saving up for a larger capacity 1TB SSD but in the meantime would like to upgrade the OS so I can get rid of this hellish pop-up which I have read can only be dealt with by upgrading the OS and for better & more stable performance. As my MBP is old now & will still be using a mechanical HDD for the time being, someone suggested to me that I should only upgrade up to El-Capitan & no higher till I get an SSD fitted - may I ask, is that the right choice for my machine & situation or will another OS work/be better? I have been able to make a bootable usb stick of El-Capitan by using Diskmaker X. As my MBP has had a bunch of older OS iterations installed in the past & due to the sluggish performance, I am considering doing a clean install so I have as fresh a system as possible & without any crud from the past that may still affect things. I also read (here I think) that if one is upgrading the OS by a few generations, then a clean install is a much better thing to do - may I ask, is this correct? I know that by doing a clean install, I will lose all my data & everything on my HDD - presumably, it will only be on Macintosh HD1? I have both Time Machine & Super-Duper Back Ups in place currently. I have seen some videos on YT on how to do a clean install but they do not show the next stage which is how to move all your data & settings etc back once El-Capitan is installed from the Back Up. I have some concerns & questions: 1. I read somewhere that if doing a clean install & jumping up a a new OS by a few generations, then it is also very wise to do a “Deep, Deep Clean” - is this correct & how does one do such? 2. If I back up from say either TM or SD, will either just re-input everything as last back-up so I will have Mavericks again instead of the freshly installed El-Capitan? 3. Will all my Accounts, Settings, Apps & everything else be exactly as they were before or will I have to go through the massively long task of having to do all them all again - very concerned about this! 4. Will my Apple Mail App be as it currently is - I would really hate to lose all the accounts, settings etc and have to face receiving many, many thousands of already received emails again & having to sift through all of them - that would be a total nightmare. 5. Will Notes App still be there on El-Capitan? 6. I have a massive iPhoto Library with over 14000 photos on it - will this be safely transferred on to El-Capitan? I heard Apple had replaced iPhoto with something else & if so, will all my Photos on iPhoto be automatically transferred to this new version if this is the case? 7. I have iWork (iPhoto, Numbers & Keynote) as well as Microsoft Office For Mac 2011 which I really want & need - will they still fully work with El-Capitan? 8. Which is the better Back Up to restore from once the OS has been upgraded - Time Machine or Super-Duper & how long does it take for say 500GB of Data? 9. What is the best, easiest & safest way/process to restore all my Data back once exactly as it was before once the clean install is done? 10. Is there anything else I should do, be aware of or have not considered? Very sorry for the long post but as you can probably tell, I am not the brightest spark around so wanted to provide as much info as possible! Many Kinds in Advance! Bazzy!