Shuttle SFF bootup Issues

Hi,

I have a problem.

Till recently, my Shuttle SFF pc was humming along with specs as listed below. then my optical drive died.

So, I purchased a new DVD writer (SATA) to replace an older DVD writer that was EIDE, since there were SATA ports already built into the Mobo.

After I installed the optical drive, Windows XP refused to boot complaining with the following error message "boot disk failure insert system disk and press enter"

So after I scandisk'd a bunch of times (never revealing any issues), I spent significant time googling for a solution.

In the process I made the following discoveries:
1) The HDD based WinXP ( in Drive E) will boot successfully if and only if either of the following are performed
- (a) A bootable CD should be in the optical drive during system bootup (Win XP install or BartPE, either works). This, despite the fact that I don't press a key to boot off the CD
- (b) I disconnect the SATA optical drive from the Mobo

2) If I try to boot into BartPE, the system fails with a BSOD.
3) If I try to boot to the recovery console to try a "fixmbr", I meet with a BSOD.

So, my question to to y'all is - why is the system behaving this way?

My system specs and changes are listed below.

Thanks very much for your inputs!

Regards
Vinu




Previous specs
1. Shuttle ST61 motherboard + Pentium 4 @ 2.8 GHz +1.5 GB RAM
2. Two EIDE HDDs partitioned as follows:
-- a) 150GB partitioned 3 ways -
---- C = blank (122.5 GB)
---- E = Boot - Win XP OS (25GB)
---- G = Pagefile (2.5GB)
-- b) 300 GB drive partitioned 2 ways -
---- H = User data (195GB)
---- I = Backup (105 GB)
3. Lite On IDE DVD writer

Change to spec
Replace the Lite On IDE optical drive with a SATA DVD writer from LG (GH22LS40)