I have opened my xls files double clicking it up to now.
But now I can not do this. The Excel program strats properly,
but it does not open my file, I get a default state as if I closed
my all files in the Excel. After that I can open my file from
the Excel correctly. So I had to open the file twice and it
is very annoying.

I got a Office XP. After this problem I have upgraded to Office 2003,
but it did not help me. References to extension (e.g. .xls) are
good in Windows (the Excel starts correctly)

Every xls cause this problem (even the simliest xls file)

What is the solution? Can anybody help me?
Thanks,

Danyi, Attila