Super weird problem

I have a really strange problem. I've implemented a website using a lot of user controls (ascx). Everything worked fine before, and it has run for months.

And today, suddenly all those user controls (scrolling messages, tabstrips, menu, etc) don't work anymore, i.e. nothing appears although there's no error message. And I do not change anything, the codes remain exactly the same as before.

The web controls (textBox, calendar, buttons, etc) on the main page (not in ascx) still work fine.

I've spent, in vain, a lot of hours trying to figure it out. Do you have an idea what's going wrong ? I really appreciate your help.

Thanks

Btw, the codes are quite long, so I won't post it here. But if you need to see a part of it, just let me know, I'll post it.> nothing appears although there's no error message.

What exactly do you mean, "nothing appears"? If you View > Source, what do you see? Have the ASCX controls not be added at all? Or have they been added but not rendered?

Also, the elements you mention as having ceased to work look as though they'd use Javascript. Even if you haven't changed the ASCX or ASPX files, have you perhaps changed an external javascript file? I once forgot to add ";" to the end of a new line of script ... and it broke myentire site!
Things always get broken when no one has changed anything :)

If truly nothing has changed, try resetting IIS, as something might be confused in there...

Most likely though, as SomeNewKid2 said, it might be possible you made a change to something and didn't think it would even affect the controls...

But I could be wrong too :)
If the site is being hosted, I would check with the hosting site that they haven't upgraded the .net framework to 1.1.