For some reason, none of my Excel 2003 files will open when I double-click
them from a folder or desktop shortcut - the only way I can open a file is to
start Excel, click open and browse for the file I want.

As a side note, I was recently attempting to get my workbooks to open in
separate windows as opposed to multiple files open under the same heading -
i.e. I wanted each file to have it's own toolabar, etc. After reading several
discussion posts, I tried clicking ToolsOptionsViewchecking "Windows in
Taskbar" and ToolsOptionsGeneralchecking "Ignore other Applications". I
also went to WindowArrange and tried checking horizontally or vertically,
although this did not give the result I wanted, since it simply put the
workbooks horizontally or vertically in one window instead of distinct
windows. However, after closing down Excel and reopening it, the files are
now in distinct windows, but this problem of opening files has arisen - the
above changes are the only ones I've made recently, so I was wondering if any
of those could be the problem or if there is another solution.