How to get my Nikon D5000 to auto focus again?

I've had my Nikon D5000 since last april, and it auto focuses when i hold down the shutter button, but last weekend it wouldn't and i had to manually focus it, which i don't have any problem doing i'd just like to be able to capture a picture quickly without having to take time to focus it right.i've tried to look at all the menu settings and stuff but if you have a way i'd appreciate it.

I just got a Canon EOS-1d Mark III?

Body of the camera only, I'm switching from My Nikon d80.
To this camera, and Honestly I got this camera second hand, from my husbands father.
and I'm a little overwhelmed as I haven't had the chance to use it yet.
Just wondering what is a good starting lens for this camera.
as far as mm wise.

if you could give me a brand of a lens and how many mm you would suggest for a starter lens on this camera, I will be using it for portraits, and then also for some cityscape pictures and nature photos but mostly portraits, I know it is made mostly for shooting sports and high action photos, but what lens would you suggest for portraits and some close up photos, and the brand and mm of the lens.

Quick Help? Does light-writing with a laser pointer harm your camera?

I have one of those cheap little red laser pointer key-chain things and I was wondering if I could use it to light-write with my Nikon D80 DSLR or if the laser would mess up the insides of the camera?

Please let me know as soon as possible because I'm taking my camera out tonight.

What other Lenses can i use on my Nikon D3100 other than nikon lenses?

I ust bought a D3100 with the 18-55mm lens i was looking at buying a 55-200mm but before i did that i was wondering if i could use other brand lenses with this camera? I'm new to the whole SLR thing the D3100 being my first one. What lenses should i buy when i start looking into getting new lenses? I have alot more questions but i guess i will face them as i go. Any suggestions or info would be great!

Should i feel bad for spending money on my camera?

This is really weird, but i feel bad for spending $930 for my Nikon D90. I had been saving up money for a while to be able to get it, and my parents helped me out by giving me money for my birthday, christmas, etc. Now that i have the money, i just feel bad, like i shouldn't be spending so much money on it even though i know i'm going to use it a lot. Would you feel bad spending so much on a camera? It's mostly because the money i saved up was mostly from my parents, they willingly gave it to me though. I was planning on getting a job to save up, they just wanted to help. :l

Added (1). It's the 18mm-105mm lens kit, not just the camera. By the way, i haven't bought it yet. I'm highly considering it though.

How much should I ask for when selling my camera?

I have a Nikon D3000 and want to sell it to get a Canon t1i or t2i.

What I want to know, is how much I should ask for my Nikon.

This is what I have:
Nikon d3000 body
18-55mm kit lens
35mm f1.8 lens

Also have a camera bag and a 2gb sd card. Everything is in like new condition.

10-24mm Ultra Wide Angle Zoom?

I know people are going to read my question than ask my photography background so I figured I would give a little bit of my background first than ask my question.

I'm currently a student photographer I have been hired to shoot some weddings in the past. I wouldn't consider myself a amateur I'm more of a (advanced to semi-pro) photographer. I have sold several sports prints of my work, and although I do shoot a lot of sports I have been starting to dabble in panoramic nature shots.

My question is I have always done my nature shots with my standard Nikon 18-55mm zoom, but have been thinking of buying the Tamron 10-24 Ultra Wide Angle. So I guess my real question is how much wider of a shot will I get than using the standard 18-55mm.

If anyone is wondering about my mounts I shoot with a Nikon D60, and Nikon D7000

Problems with DSLR - help fast?

When I put my 18-70 mm lens on my Nikon D70, the top right corner of the screen flashes F- - and will not take pictures. The only way it will take pictures is if I put it on M, and when that happens the picture is dark and nothing shows up. Adjusting the ISO does not help. I have tried taking the lens off and on again, many times. This has never happened before. When I put my other lens on, it's fine. Any tips, I have my first big photo shoot tomorrow! Thank you! I will be happy to add add'l info if you need it.

Tips for taking amazing night/dark photos?

I have my first photo shoot where I need to take pictures in a dark setting. It is a prom, and I'm very nervous. I have a Nikon D70 and I will be renting an external flash. Are there are any good settings I should set my camera to? They will be candid shots, likely of people dancing. Any suggestions are great - thank you!

Added (1). I have permission to use a flash.

I only have an f 3.5-4.5 lens, which I know isn't great but if I get hired full time or whatever I will get a better one. More tips appreciated! Should I use the M, A, S, or P setting on the camera?

Nikon D40 - slave flash units?

As a college student I'm limited on budget for better photography equipment. I currently have a Nikon D40 with the SB600 external flash. I was wondering if these following items would be sufficient to remotely trigger my external flash with the D40.

http://cgi.ebay.com/...2c56264b24

and a Yongnuo Speedlight YN460 II slave flash unit.

I would certainly prefer a SB900 and a pocket wizard over these items but I'm on a limited budget. Will there be anything else that I would need for these items? Other than the obvious for light stands and diffusers. And any other advice and suggestions are certainly helpful. Thank you!

Added (1). Or http://www.amazon.com/...0046HGYQ2/

or

http://www.amazon.com/...002W3IXZW/

would these items work with my camera and sb600?