computer freezes up for no aparent reason

computer freezes up at anytime could be doing something could be just sitting , sometimes during start up and if I'm playing a game it just stops and the audio skips forever also the computer been through alittle the cpu is about two years old but since then its been in all new hardware config twice always with the same mobo though I've reinstalled about 30 times since I've got it ,I got a new case a year ago and didnt use spacers between the mobo and the case and it cause the atec 400watts to burn , then got everything tested and it was straight the cpu and the mobo installed everything and it ran fine it wasnt till I got a new harddrive a 300 seagate that everything started to **** up I couldnt get the new one to run as slave and the bios wouldnt load then I got it to run slave and it lost some space and it wasnt half or anything i have xp and a newer shit so its not like it only can run 300 or 250 or whatever the older shit can so I got it to all work again once I reset the cmos and reconfig everything with the drives but then and I reinstalled and everything work till I updated things then stuff started messing up the ht ON the cpu didnt work and the 300 wasnt execute certrain parts of files that were on it (mostly media) so I reformated and ran and lost like 15 gbs of space on it ? then everything was alright for alittle bit but I couldnt get a driver to update on my ati tunner pro and then it wouldnt work right and then it would come up with the windows installer for ever then I reinstalled and everything ran ok but then it started doing what its doing now with the stoping in the middle of something not all the time but atleast once or twice a day the mouse won't move and everything stay the same on the screen to what it was when it stop working no blue screen l

 

so u think its the HD thats causing the problems...? u could use HD Tuner to check it for errors. a little more details on ur spec would be helpful