There are few possibilities that ur system is a pain.Ok here is what the possible solution:
1.Update BIOS(updated).
2.Update all the drivers including sound,motherboard,display,DirectX etc.(ALL LATEST).
3.Install a fresh copy of operating system with all updates.
4.If HDD is running too hot then install a HDD Cooler,'ll cost u around 250/- for a local one but its worthy.I 've seen a HDD cooler with 2 Fans on it.
5.Do a memtest for 20-30 minutes(1 Hour recommended),This will show u if u have a faulty memory.
6.Reassemble all the parts of your system.
7.Properly connect every cable & check the ventilation of ur cabinet.
If this doesn't help then change the motherboard & buy an ASUS,MSI,GIGABYTE,A-Bit,DFI etc. BUT NOT INTEL ORIGINAL.
-What is PSU specs?(how much Wattage?)
-Have u overclocked ur system?