lion start-up and problems with last file opened

Just installed Lion 2 days ago and the computer runs very slow with Lion. Only bought it 4 months ago.

Also, now when i go to Safari, Excel or any other program it opens up the last page I was in. In Safari it does not go to my home page, but to the last page i was on. Same with Excel. Instead of opening to a blank page, it just opens up the last document I had opened. this has all changed with installation of Lion!!

thanks for your help

tim