Problem with hard drive upgrade.. Help!

I have a dell inspirion 1505. I just upgraded my Ram and my hard drive. My computer came with a 80GB hard drive, but when i tried to replace it with a new 500GB hard drive my computer still only recognizes it as a 80GB. During the windows 7 upgrade where i would normally be able to clear my new hard drive and specify my new drives it still only showed 80 GB. i have talked to dell twice now and i get conflicting answers each time. The first person said that my computer would only support 120GB and the second said it would only support 100GB. I have a hard time believing this because my computer came with a SATA harddrive, which shouldnt limit me.. At least i thought. Any help would be much appreciated on this matter. Thanks!!

Sounds like the BIOS needs to be told about the new drive. The fact that your machine still sees only 80Gb would indicate that the BIOS isn't seeing your new drive.
Have a look in the BIOS and see if that is the case.

I checked during bootup, under the device properties it only says 80GB. Any suggestions?

I took a look at the Dell site and the largest drive they have listed was a 120GB Serial ATA-150. This could be why their phone support made that statement. Phone support will only tell you what is written in front of them.

There is however the problem with the first generation SATA controllers not knowing how to handle the newer SATAII drives. For these drives there is a jumper to force the newer drives to use the older SATA transfer rates. I have know way of knowing all the side effects of using a SATAII drive on a controller that doesn't know how to control the drives properly.

I tried upgrading the bios, still no luck. Is it possible that there are other flashes or drives that i can download to turn my hardware switch over so it recognizes this new amount? I have been told that it is possible from several computer repair people.. but no luck on an exact answer

Since you already updated the bios and are having no luck, it does not look good.

You could try pulling the cmos battery out for at least 10 seconds or so then put it back in.

It's a circular silver disc on the motherboard, commonly with the name Sony on it. It's retained by a plastic holder with a little clip you can gently push on.

Here is a picture of the battery