I found DELL's notes on installation helpful but certain things happened not as described.

 I have 5 month old 64bit INSPIRON  660 with INTEL  i5 processor.and preloaded Microsoft Office 2010.

1. No need to download Office patch apparently does not apply to 64bit system.

2. McAffee anti-virus did not need reinsallation. It self installed 61% through installation. 

3. Free version of Media player available as special offer with discounted WINDOWS upgrade

4. Needed to uninstall DELL Stage during installation though no message Upgrade Assistant.

5. Worst problem was need to uninstall Intel(R) USB3.0 eXtensible Host Control Driver during install process. I thought I had downloaded all latest drivers from DELL Download System and I ignored warning. During upgrade it started to uninstall and locked with mouse inoperable. I pressed enter it unlocked but put me back to desktop. Luckily there was an Upgrade WINDOWS icon which worked and it continued to end.

With respect to WINDOWS 8 I found it easier than I thought. (Download info from TOMS site) but three remaining problems.

1 Have old XP Programme which needs old version of help. The fix for win32hlp.exe from Microsoft downloads but does not run

2. System Restore to my external hard drive  says that when it does next scheduled restore it will wipe my old WINDOWS7 backup I took before upgrade.

3. If you have software needing non default keyboard entry the means of changing language is horrendous