Odd that it would suddenly pop up like that -something must have changed.   There's always the quick and easy "system restore" to undo whatever happened - Start, Programs, Accessories, System Tools, System restore.

A few other ideas:

1) Start - Control Panel - select Tools from the top menu, then Folder Options.   Under File Types, scroll down to JPEG types and see if you can change the default JPEG file associations to what you want.

2) Have you actually uninstalled the trial from Add/Remove, or is it still there?  If it's still there, uninstalling should give you the option of removing all the file associations.   If not, Corel has a removal tool that might help remove the remnants, from an article that's similar to your problem:

http://corel.custhelp.com/cgi-bin/corel.cfg/php/enduser/std_adp.php?p_faqid=758347&p_created=1115063535&p_sid=r7HXP7Mj&p_accessibility=0&p_redirect=&p_srch=1&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MTYsMTYmcF9wcm9kcz0wJnBfY2F0cz0mcF9wdj0mcF9jdj0mcF9zZWFyY2hfdHlwZT1hbnN3ZXJzLnNlYXJjaF9ubCZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXphcA!!&p_li=&p_topview=1

3) As a last resort, there are tools that can reset the file associations to default - I trust the sources, but still get the willies when messing with the registry:

http://windowsxp.mvps.org/imgassofix.htm

http://www.dougknox.com/xp/file_assoc.htm

Thanks for the suggestions. Will work through some of them - the ones I feel safe trying. The 'willies' is an understatement for me doing anything beyond the very routine. Worst case is I can save the atchs to desktop and open from within a photo application.

Don't sweat it too much.   The rule I follow is if I try something and it breaks, at least I know what broke it.   That's more than half the battle.

One more thought.   Is this Outlook Express, and did it start having problems only after you installed IE8?  Or maybe after the big MS update in mid-October?

There have been a lot of reports of problems of IE8 getting along with Outlook Express.    Part of the problem is that OE was originally bundled with IE and shares a lot of functions with it, but Microsoft  doesn't support Outlook Express directly anymore  - the last "bundle" was IE6 and OE6.

If that's the case, rolling back IE8 to IE7 is another option.    Or, there's the option of trying Windows Live Mail, which is MS's free replacement for Outlook Express and is more independent of whatever's going on with IE.

Thanks for the input, everyone.  FYI here's what eventually worked: As suggested, I removed the expired trial software, then changed the file associations in XP by following these instructions::

Change the program that starts when you open a file

Applies to: Microsoft Office Access 2003, Excel 2003, InfoPath 2003, Outlook 2003, PowerPoint 2003, Word 2003

Many file types in Microsoft Windows XP and Windows 2000 are registered to be opened by a particular program. For example, Notepad starts when you want to open a text (.txt) file. You can change the program that starts when you open a file of a certain type.

1.     In My Computer or Windows Explorer, click the Tools menu, click Folder Options, and then click the File Types tab.

2.     In the Registered file types list, click the file type you want to open with a different program, and then click Change.

3.     In the Open With dialog box, select the program you want to use, and then click OK.

4.     Click OK in the Folder Options dialog box.