i tried to install RHEL5 in my pc in the step where it asks for media ( local cd drive, hard drive, http,ftp,etc..) i selected cd drive its asks for drivers in the beginning and i dont know what drivers to select. i selected default intel sata driver then also it asking for drivers.

my pc configuration
Intel core 2 quad,
8 gb ram,
1 TB and 260gb sata HDD( i need to install in 260 gb Hdd)
sata DVD drive

That means it doesn't support your motherboard's chipset. Since RHEL is a Server OS it may not work very well or at all in some modern desktops and laptops. First thing to look at, make sure you try the latest RHEL5.5.

If you really have to install the Redhat Enterprise Server OS :

You will have best chances with the latest = EL 5.5 .

Or the Fedora 12 based EL 6 :
http://distrowatch.com/index.php?dis...h=all&year=all
..

my mother board is intel DG45ID!! is it compatible!!
is it possible to install ANSYS 12 in fedora 12 based EL6!

If you want to know what's compatible with RHEL5, why don't you CALL REDHAT, since you're paying for support with your RHEL5 subscription, right???

If you're not paying for RHEL, don't use it. Use a community-supported version. The latest RHEL5.5 should work fine with SATA drives/controllers. If not, RHEL support can help you get through it. Fedora 13 will probably work, as would CentOS. Have you checked the Intel site for drivers for Linux? And have you checked your BIOS settings?? Sometimes setting the SATA controller to emulate a legacy drive works...