My 400d will not fire all the time, unless I push and rub shutter release button!!

So my Rebel xti is having an issue. Sometimes it wont fire at all, and I literally need to rub the shutter release to make it shoot. Even then, it takes a good 10-15 seconds to take a shot, every time!

No matter if I have it in av, tv, p, m, etc. The battery is fully charged, I've tried all my different lenses, and even tried different memory cards. Same problem. It auto focuses fine, but then it wont shoot. Please help!

This is pretty common for at least the 40D. Search here and you'll see. If you have a remote control, you can try that. If that's fine, then you know for sure it's the button itself.

Broken shutter button. Typically takes Canon service two weeks and US $250 to fix.