Old Gateway PC & Large Drives

This is my first post on this forum, so please forgive me if I inadvertently break any of the rules of etiquette. This is a bit long but as no 2 PC’s are the same I thought it best to give as much information as possible.

I have a UK delivered Gateway Performance 550XL PC which I bought in May 1999. A quick overview of the main components and the changes I have made is as follows:

* Intel 550MHz Pentium III processor.
* Intel (Tabor 2) BX motherboard (model 4000484).
* Motherboard chipset Intel 440BX chipset and 512K L2 cache, although the actual chip has 82443BX printed on it.
* 15GB hard drive (no longer present – see later notes).
* Promise Ultra ATA 66 controller card (2 connections for up to 4 drives).
* December 2001, the original 128MB of 100MHz SDRAM (168 pin DIMM) upgraded to 640MB by adding 2 additional 256MB boards purchased from Gateway/Kingston.
* September 2002, an additional 80GB hard drive fitted.
* At this time, under the advice of gateway support, the Phoenix BIOS was updated from version 4W4SB0X0.15A.0013.P08 to version 4W4SB0X0.15A.0019.P14, downloaded from the Gateway web site.
* June 2004, another 80GB hard drive fitted and the original 15GB drive removed. All drives are Ultra ATA/100. Both 80GB drives are fully “visible” to the system.
* April 2006, Windows 98 operating system replaced with Windows XP Pro with SP2. (clean install).
* All housed in an ATX full size tower case.
Phew !!

So far, all the upgrades/changes have been made without problem and everything is running fine. My current problem is this:

Both the hard drives have become noisy so I am replacing them before they start to fail. I have bought 2 x 160GB Seagate drives (ST3160815A). I have tested the drives in the PC but WinXP Disc Manager is only recognising 137GB on each drive.

I have done lots of reading up on all this – so much so that my head is still spinning. So the questions are:

* Is my current PC setup capable of handling two 160GB hard drives?
* Is the bottleneck the motherboard itself?
* Is it the system BIOS?
* Can the system BIOS be upgraded?
* I’ve read that there is a separate BIOS on the Promise controller card – can this be upgraded?
* I’ve read that having the controller card removes any limitation that the motherboard BIOS may impose – is this correct?
* If upgrades for the motherboard and/or controller card are available, how do I know which versions are needed, where do I get these upgrades from and how do I apply them?
* Is there some other limit in my system?

I have used the free version of “Driver Agent” and it identified the existence of updates for the Phoenix BIOS, the Promise ultra IDE controller, the PCI master IDE controller and the PCI bus master IDE controller. But I’m not sure this can be completely trusted.

Really, 137GB on each of the 2 drives is more than enough space for my needs, but it would be good to sort this out if it can be done.

Whilst the system boots up and the disc info is displayed prior to WinXP loading, it shows the drives as LBA and DMA mode 4. But I’m not sure this implies 48bit LBA.

I have managed to “see”, partition and format all 160GB of the new drives using a bootable version of Seagate’s “DiscWizard”, but this seems to upset WinXP’s Disc Manager.

If there is no solution, then as long as I create partitions which only use a max of 137GB on each drive (leaving the rest “unallocated”) will there be any danger of data corruption, overwriting or wrap-around?

I have looked on the Gateway web site but my system is not supported any more, certainly not with WinXP. So, any help, however small, would be much appreciated.

George.