This question has been asked before here at Experts Exchange, but not resolved (back in January 2009) -- I am having the EXACT same issues.
All Files are being saved in .xlsx format. Still locks every time I open an Excel file. Very Frustrating. Do a Google Search of: "Excel 2007 Locks Up" and see the hundreds of others dealing with this same issue. Microsoft was NO HELP and they now want $249 to trouble-shoot their their buggy software! No way. I'll dump Excel before I pay them to fix their flawed program.
Any clues on what is cuasing this? I have a newer i7-920, 4-GB RAM, Windows 7 (32-bit) - ATI Radeon 4770. System is very fast and very stable -- except for Excel!
The prior post on this issue here at EE was asked here:
Thanks for any help!