Just bot a Dell C521 with 3600+ 512mb RAM.

Tried to install FC6. Cannot do it in GUI mode (the whole installation runs but the machine hangs when it reboots itself for the first time).

Installed it in text mode but whenever I startx, it hangs. I can CTRL-ALT-F1 to come back but that's as far as I went.

I looked all over the web but it seems that people had problems but I cannot find a solution. Any suggestion MUCH appreciated..... THANKS!

What graphics card is on that machine? Sounds like a probable candidate for the problems. In text mode try to have a look for error messages in /var/log/messages
If it is the graphics driver, try to install a new one from text mode. You might want to boot directly to text mode, or after it has hanged and you go to the terminal and run "init 3" to reboot to text mode without gui. Then log in as root an install a new graphics driver. If you have a nvidia based card, download the latest from their website.

You can also try the dmesg command from text mode to look for error messages.