Perhaps, most of us who ever tried to partition a drive manually (not using XP Setup CD) have seen a boot time error where it says "disk read error" or something similar coming from BIOS.
There was quite many thread about that in newsgroup. Here is one of the latest.
I am not going to go deep here and explain why it might have happened if you used Microsoft tools like diskpart and etc. Just keep in mind that tools like diskpart are intended to be used by IT technicians who know their stuff and dealt with similar partitioning problems many times. Now you also do :-)
I found it extremely easy to repro the issue if you use VPC (Microsoft Virtial PC 2005-2007). Just create a new image there and partition the drive with diskpart. Even if you set the system partition active, you may end up with no booting image because of the screwed MBR record. This of course tends to be the case from machine to machine. I mean it is not 100% reproducible if you move to another PC.
The fix is actually quite simple. I posted it many times:
- Mark the system partition as active if you haven't done so.
- Try fixing MBR. You can do it manually (just have to get used to MBR binary flags and partition table settings) or you can use MbrFix tool I mentioned in the newsgroup and in this blog. MbrFix tool is lovely and provides lot more functionality.