Weird issue. My Snow leopard can't start and keeps looping

Hey there,
I would really apreciate it if you could help me on this one

The issue:
Every time I start my iMac it happens as follows:
1 - first the grey screen with the apple logo - good
2 - the original snowleopard wallpaper (pink cosmos) apears and asks me to log in - never happend so far; i type my password and hit log in;
3 - for a few seconds I can see my custom desktop... for let's say 2 seconds
4 - suddently the blue screen appears for 3 seconds
5 - then it returns to the step 2 asking me to log in again
.... and so on, looping forever.....

What happend:
I've just moved to a new place. My old iMac worked just fine after assamble and I wanted to connect to the interenet through cable. I tried several times to connect with the username and password for the network.. and it didn't worked. Then I oppened the Network Utility and my mac freezed for quite a long time. Then I pushed the back on\off button to restart.

At this point after opening it, after the gray+apple logo it appeared only the blue screen with the small circle thinking thing, over and over.
I've done a permitions repair and a disk repair from the instalation dvd, and after that it starts looping as I have first written.

What I did so far and didn't worked:
1 - taking the network camble out from my mac
2 - puling out the power cable, cables from the keybord and all the plugged usb
3 - making disk and permitions repairs from the original disk - Hdd seems ok
4 - log in in the safe mode (the same loop happens)
5 - do a "fsck -fy" repair - Hdd seems ok
6 - make an advanced hardwear search from the second original install disk (the push D key thing) - no problems appeard

My system:
the previous Imac 21.5" led generation, snow leopard
4Gb memory, dual core intel at 3.something , 1T hdd - almost full.

I have no backup done, or Time restore thing. My bad, I know!
Please help!

Get an external drive, format it GUID and install OS X.
Use the external to start/boot your computer.
Copy all your important files to the external.
Now reinstall OS X on the internal.

Do you have an alternate user you can try logging in to?

Thanks gsahli,

that's what I did after all. I've bought an external hdd.
Before this I have taken the risk and I have reinstalled the osx over the mac... no errors or anything, but the problem still remained. I suppose it is normal since the settings of the applications remained the same.

between333 said:

Thanks gsahli,

that's what I did after all. I've bought an external hdd.
Before this I have taken the risk and I have reinstalled the osx over the mac... no errors or anything, but the problem still remained. I suppose it is normal since the settings of the applications remained the same.

Click to expand...

Since you are still having a problem, do you have another user you are able to log in to? In other words, is this problem isolated to just one user account? If so, this sounds much like a problem I had with my wife's user account. The only solution was as follows:

1: Boot from an installation of OS X on another partition.

2: Migrate her user over to that from the primary partition.

3: Boot back into the primary partition and delete her user account.

4: Migrate her user account on the secondary install back over to the primary.

If you have current Time Machine backups, you can bypass steps one and two and simply perform step 4 using the Time Machine backups. As I said, this is the only thing that worked, and believe me, I tried a lot of radical tricks to try and isolate the problem. Whether or not it will fix it for you, I cannot say for certain.