About the crash

So, about the crash, as I mentioned it was on my main PC. This is ironically the PC I'm moving everything to because of the random shutdowns on my other PC - by "everything" I mean the Palm desktop software which I use to get blog entries from my handheld (where the first draft of most of them are written), and iTunes and a ton of other software.
My PC's hard drive is partitioned into at least 2 partitions: the C drive which basically contains Windows and Program files and a D drive where most of my data and documents is stored. I'd initially partitioned the C and D partitions the same size, but was starting to run out of space on the D partition. So, I fired up Partition Magic, which I'd used to partition the drive on the first place, and shrunk the C drive and expanded the D drive. When I pressed the "Apply" button, Partition Magic rebooted Windows XP and went into batch mode to do its magic. When I checked on it later it had some error message - I didn't write it down although I probably should have. Anyway, next thing I see a Partition Magic error - which is never good. I rebooted the machine.
Windows seemed to boot up okay, although the Start Menu task bar looked a bit squeezed.
I ran a check on the D Drive with Partition Magic but no errors were found.
Then I ran a CHKDSK on C Drive and it displayed all weird errors and showed messages about invalid security for file number (starting at 1 and going through to around 2000) - security set to default.
After rebooting the machine Windows was a mess - no Start Menu or TaskBar and two programs DISCUpdate and DISCHub were using 100% of CPU. I killed them and tried to copy some files to an External Hard drive, but the copy and paste wasn't working (Neither was drag and drop).
After trying to research the problem online I figured my best option was to restore the C Drive. This took 3 tries, but now Windows XP is back minus whatever programs I installed since December last year. Of course my Documents and data on the D drive are still there.