STOP: c0000021a (fatal system error)
The session manager initialization system process terminated unexpectedly with a status of 0xc000003a (0x00000000 0x00000000).
the system has been shut down.
Yes, that is windbloze complaining. See this link, -->http://www.wiki-errors.com/wiki-erro...iki=0xc000003a
Did you install Lilo to the master boot record? If this is the message you get after re-booting, I would bet you did not.
Here is a link to help you install and get it running. If followed, you will wind up with a correctly installed Slackware system, and no winddoze messages.
BTW, formatting by itself will not wipe the MBR. You would have to re-partition first, then format.
Have a look through the Installing Slackware link, the Basic Setup, and Package Management links. All good stuff.
Slackware has newer releases now. Current is 13.37, available in 32 bit and 64 bit releases. Best of luck with Slackware.