I don't know how to open the camera to put my film in...

I've been seeing a great number of posts from people requesting help with a stuck film advance feature on their 35mm film cameras (you remember "film", right?) Normally, there are just a couple of things you can try to fix this issue before you'll need to find a professional to repair your camera - if it's even worth it. On that note, a lot of people still have film cameras for nostalgia purposes but there are still some hold outs that enjoy film. Finding a repair shop for an older camera isn't impossible but they are getting scarcer. Google "FILM CAMERA REPAIR" and see what pops up in your area!

MANUAL ADVANCE CAMERAS:

There's a complex number of actions that must work properly in order for you to advance the film in your camera using the manual advance lever. Gears, shafts, bearings and springs come into play and like a clock, they need to mesh together or the advance mechanism comes to a screeching halt. Well, you'll be the only one screeching, most likely but you get the point. If any of those parts break or become unaligned, or if some foreign matter like dust or dirt gets into them, the same thing happens. However, there are sometimes a few things you can try that might prevent you from sending in your camera for professional repair. I caution you about opening your camera yourself unless it has no real value to you because the interior of a 35mm SLR camera is pretty complex, even more so that a clock. Chances are you'll do more bad than good. With that said, try these options:

Film Jammed - Won't Advance
Sometimes the film will jam in the canister, or in rare instances, isn't actually as long as it's supposed to be and can reach the end of the roll before the camera indicates it has. If you suspect this has occurred then push the film release button and try to wind the film back into the canister before opening the camera. If you don't care if the film gets exposed feel free to do this in the light. It's much easier!
At times the film may also pull lose from the canister and roll completely on the take-up reel. If this happens you'll need to take the camera into a completely dark room with the light-proof film container, remove the film manually from your camera, roll the film up and put it into the light-proof container, close it tight and then seal it with electrical or duct tape. Also let the lab know this has happened so they don't pop up the container and expose your film thinking it is still in the canister.

Advance Lever Stuck
If the actual film advance lever is stuck and won't move, about the only option you have is to open the back of the camera and be sure nothing has jammed in the gears or sprockets of the take up reel or film path. If that doesn't fix the problem try pressing the film release button, wind the rewind lever a bit and see if the advance lever engages again.

If the lever just flips back and forth with no tension at all then something inside has broken and your chances of repairing it yourself are almost none. Most film cameras are getting on in years and will just naturally begin to break down over time. There may be no option to even fix your camera unless you find a similar model for parts and send that along to the repair shop. Make sure you get the parts camera back as you may need it later! If you like tinkering and the camera isn't one you'd miss if you couldn't fix it, then you could always give it a shot yourself. You can pick up a set of jeweler's screwdrivers and pliers from the web or Radio Shack for under $20 and find old film cameras on EBay or Craigslist at a decent price. Just be sure they don't have the same problem as your current camera does!

Grinding Noise When Advancing Film
This is most often caused either by a broken part, metal shavings or dirt/debris in the winding mechanism. Again, if you feel comfortable doing it yourself and it's not an expensive collector's model, you can try to repair it yourself. Hunt down a PDF service manual for your camera on the using Google web (a lot of collectors share them) and it should show you how to remove the cover to see the winding mechanism area. Look for debris in the gears and springs and remove it with short blasts of canned air but be sure you hold the camera so any debris falls out and not further into the camera. You can also use Q-tips dipped in alcohol to remove any debris, but don't use water, and let the area dry completely. Once you've done this, you'll need to apply a light lubricant to the area but only if it was lubricated before you cleaned. Use thin white lithium grease or an oil or grease used by clock repair shops and apply it with a toothpick as you don't need much. DON'T USE WD-40! It will do more damage than help.

MANUAL ADVANCE CAMERAS WITH MOTORDRIVE ATTACHMENTS:

These are manual wind cameras like the Minolta X-700 or Nikon FM2 that have an attachable motor drive that winds the film for you. Pretty much the same suggestions previously noted can be tried with a couple of exceptions:
Check the batteries and contacts in the winder making sure they're clean and not bent or broken. You can clean battery contacts with a CLEAN pencil eraser or alcohol and a Q-tip. Blow any dust and debris out of the compartment afterwards.If you still experience problems remove the winder and be sure the coupling that locks into the bottom of the camera to wind the film is not jammed or damaged. With batteries in the winder and the power turned on, look for a series of contacts on the top of the winder that mate with your camera. Be sure these aren't dirty or broken as well. Using a paper clip, you should be able to short one or more of them to another to activate the winder to make sure it works properly.

When All Else Fails - A Bigger Hammer
If none of the previous suggestions work and if, ONLY if you don't value the camera for collector's value a firm tap might work as a last ditch effort. I once had an old Minolta SRT that locked up solid. I didn't want to bother with trying to open it up as I only used it for a shelf display so I took the lens off, used a wad of very clean, soft foam to hold the mirror steady and wacked it twice on the counter. Not enough to damage the camera body (or the counter!) but a good smack. Whatever was jammed came loose and the advanced began to work. As I said, I only use it for display so I don't know if it affected the shutter speeds, etc. but it worked and cost me nothing but time.

AUTO/POWER ADVANCE CAMERAS:

Newer "old" 35mm film cameras used a power winder motor to advance the film and **** the shutter. If you experience a jammed advance on these cameras, check the film path, sprockets and make sure they are clear and move freely, as I described previously. Try the film release button and see if that will release the drive as well. Another option that has worked at times is to remove the film, lens and all batteries from the camera (including any date/time battery) for at least a day or two to see if the camera will reset itself. This worked for me once with a Nikon N70.
As a last ditch effort, the table smack might work as well, but I make no promises and it's all your fault if you damage the camera beyond repair... or your furniture!