Excel 2007 Save and Save As Problems

Hi

I'm having difficulty saving Excel files, both in 2007 and 97-2003 formats.  Some of the files are quite large, but not ridiculously so.  Excel frequently hangs during the save operation and, even when it does manage it, it's still really slow.  The problem is worse when saving across the network, but pretty bad when saving locally.  It's quicker if all the file links are broken but, obviously, this is not feasible for many files.  Typically, Excel crashes on me 5 or 6 times a day - more on manic reporting days.

I have heard/read various comments about it being caused by the Microsoft Office Validation, a security update, and so on.  I've also seen lots of pages that suggest registry changes.

I do remember that in my last role, the I.T. department came round and took one of the Microsoft updates off the machines to resolve this (can't remember which one).

Does anyone have a definitive answer that will definitely solve this?  The problem seems to apply to Access too, though that might be for a completely different reason.

I don't have administrator rights on this machine (damn them!) but if I have some kind of good reason why they should go down a particular path, I think I.T. will be prepared to try it.

I'm awarding 500 points, but won't be able to award them until the solution has been tried, tested and proved to work, so it may take a couple of days.

Thanks
Sarah