Alright i posted a topic a few days ago about how i had 2 hard drives and then i would boot up my pc sometimes my slave drive would not be detected. you guys suggested that i replace the IDE cable which i did and it fixed the problem immediately. (i did several reboots and the drive was always detected) but shortly after the IDE cable was replaced (few hours) my master drive started to lock up my comptuer (this has never happend before) and i would reboot and and the computer would run fine for about 10 minutes and lock up again. It did this about 3 times and on the third time the computer would lock up at the exact same spot in the loading screen where the blue loading bars are moving under the xp boot screen. (the bars got stuck in the same spot every time and i was forced to reinstall on another hard drive. Well everything has been fine now except for this morning when i got up my wife had used the computer right before work (the pc had been off all night) and it was locked up. I rebooted and it said the master hard drive could not be detected... I unplugged the hard drive cables and such and got it going again but i'm worried im about to crash again.

what could be the reason for what is going on here?

Well, a Hard disk is mechanical so if it happens to fail, there's not much you can do about it (do you hear weird noises?).
Sometimes heat causes problems (that would explain why it takes a few minutes to crash), sometimes it's just incompatible with others HDD. Or it's just breaking slowly... The best thing to do would be to try it on an other PC and see what happens.

Anyway, if you took it off you should be safe.

try to run a utility for testing your hdd ... there are basically 2 immediate causes for this ... hdd is going bad or if it BIOS has already turned the control over to the OS, then you might need to reinstall your OS eventually ... try running it in safe mode 1st & see if it still locks up in the very same part ... if it goes on, then there might just be conflict in the OS (usually with drivers that do not load completely) ... you may run system restore too from safe mode or pick Last Known Good Configuration from your advanced menu options ... these steps after the 1st i recommended is to rule out any software issue for the time being ...