What's wrong with my iMac?!

Hey everyone! I just noticed on Friday, my iMac began to run super slow. Facebook and my Att.net home page come up perfectly fine. But, loading Youtube or any other web page is a challenge. Actually, when I get onto Youtube finally and start watching a video, the video restarts about 10 seconds in. But, I have to click the reload button many times before any webpage actually loads. I reinstalled flash and everything, restarted my computer, and nothing worked. Can anyone please help me? I'm desperate for an answer!

Also, sometimes a webpage loads fine but most of the time it takes forever to load.

Lots of possibilities -
How much hard drive free space do you have?

Try repairing the hard drive - here's three techniques:
Resolve startup issues and perform disk maintenance with Disk Utility and fsck

That is what happened to mine before HDD crashed

I replaced the hard drive and the machine works great all but two little problems.
1-When I start to watch a video online (any video) even just little ones in yahoo or any thing else; no video player box comes up. All the print and everything else shows up but just a white background is all you see where the video should be. I hear the audio but don't see anything. If I put in a DVD it plays as it should the problem is just video. Photos show with no issue.
2-I have used firefox before but it now freezes up. I am using Safari and it works fine.

Any help would be greatly appreciated. Thanks

A P. S. to my last post

This is a 2008 24" Imac with core 2 duo, 2Gb ram, now a 500Gb hard drive.

cassidy123: the first thing I'd do in your situation is make a backup.

The second thing I'd do is run Disk Utility and see if any obvious, clear warnings come up (you'll recognise them, they're printed in red).

It sounds like a dying hard drive, but there could be lots of things going on there. How does the machine perform when you're not doing anything internet-related?

I think you both are correct

I think gsahli is correct because this is the first thing you should do is make sure there is plenty of space left on the HDD. If that is not the problem I would go with what chas_m said. Second step would be to back it up and run disk utility. My drive wouldn't run it. So I just went and replaced it. It works now except for a couple of minor issues I have not seen before. IF your the adventurous type you can replace the drive your self. I did with the help of some videos online.

This is actually my sisters Imac. She bought another one and Best Buy was going to "recycle" this one so I told her to get it back. Never worked on a mac before. I have built plenty of PCs. So for $55 I got this one up and running again. Oh and I had to buy a little tool kit ($15) from radio shack for the little Torx bit to take the case apart. It was quite informative taking this mac apart and seeing how it is put together inside too.