My sytem was not even running in safe mode

Hello,
my sytem was not even running in safe mode(including all other modes like start windows normally, DOS,...)
When i run in safe mode, system showing an alert "click on ESC to cancel loading SPTD.SYS" If i even press on ESC , system was restarting.
then i installed windows XP by using XP CD (I didn't get any repair option while installing..). then onwards my system showing 2 operating systems. i am able to run system in new OS, but couid not run in old OS.
how can i repair and run my system in first(old) OS and how to delete second(new) OS?

note: I already installed Daemon tools and SYS Defrag softwares before this problem occurred. i uninstalled Daemon tools from my 2nd(new) OS, still problem unsolved....

Please reply me as soon as possible..
thank u in advance...