Best way to move files to new iMAC
Just ordered new iMAC for my wife. Need best way to transfer data/files from her 4 yr old iMAC running OS 10.7.5. I have a backup drive and also Time Machine drive connected to the old iMAC. Can I just move the Time Machine drive to the new iMAC and use Migration Assistant to move everything to the new iMAC? Also just got the "Critical Security Warning" on the old iMAC, first using Safari and now Chrome, which postings say is a scam. Includes phone number to call for help. Per suggestions we tried restarting Safari with the shift key down but didn't do away with it. Then deleted the files "com.apple.Safari.savedState" and "LastSession.plist" and it worked for a short time but then came back. Also Google News on Safari would go blank while moving the mouse over the displayed data, then data displayed when stopped moving the mouse. My concern is this scam/bug will get transferred over to the new iMAC. Any alternatives? Help appreciated. Thanks.
iMac, OS X Mavericks (10.9.5)