I've finally solved this problem combining many ideas and editing registry.
*** PREAMBLE ***
When I double clicked and xlsx or xls file, excel opens but the file doesn't. Instead, I receive a message from excel that says file can't be located.
my pc conf is:
- vista home premium,
- office 2007 2p1
- and a lot of extra software like mcafee and acrobat...
I mixed idea of two previous solution and discussion on the web that talk about editing registry (to add quotes) and DDE conflicts with an idea of my own.
Original ideas didn't work on my pc like expected. I've wondered I had some kind on DDE conflict, so I disabled DDE through registry editing and voalá! it works! =D
*** SOLUTION ***
1.- find subkey of file that doesn't open using double click:
1.1- find extension you have conflict in HKEY_CLASSES_ROOT\ (ie: HKEY_CLASSES_ROOT\.xlxs) and then read data of (Default) value (ie: Excel.Sheet.12)
1.2.- find that value again in HKEY_CLASSES_ROOT\ (ie: HKEY_CLASSES_ROOT\Excel.Sheet.12) and look inside subkey shell\open (ie: HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\open)
NOTE: if you need, check http://www.justanswer.com/questions/1u4sk-vista-excel-2007-cannot-open
for more on this
2.- disable DDE through:
2.1- rename original ddeexcec key to ddeexec.bk (ie: original HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\open\ddeexec gets named HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\open\ddeexec.bk)
WARNING: in next step (2.2) be sure to do not rename command key; command key and command value are not the same things (keys are like folders and values mostly like files inside folders)
2.2- first, look inside comman subkey (ie: HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\open\command), then rename command value to command.bk (ie: HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\open\command\command gets named HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\open\command\command.bk)
3.- be sure correct non DDE command is set as data of (Default) value in command subkey:
3.1 Verify data of (Default) value match this pattern: "...excel.exe" "%1" /e (ie: the value which data was verified is: HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\open\command\(Default))
3. 2 If data verified do not match, then edit it in order to match the pattern. (ie: data of HKEY_CLASSES_ROOT\Excel.Sheet.12\shell\open\command\(Default) was setted to: "C:\Program Files\Microsoft Office\Office12\EXCEL.EXE" "%1" /e)
I hope to help.