Frequent crash of System

[Pranajit]

Before i narrate my problem let me give you my system configuration.
OS: Windows 7 Ultimate
Motherboard: Asus P5QPL-AM
Processor: Intel Core 2 Quad @2.66~2.7 ghz
RAM: DDR2 2GB
HDD: WD Caviar Blue 500 GB
Now let me come to my problem,for last 4 months I have been facing problems of frequent crash,system being non-functional.
And every time I do formatting,I need to format breaking the partition and formatting all the drives.Otherwise it simply doesnt format at all.gives error in any drive drive and abort the formatting.
And the problem simply doesnt stop here.
Moreover it has got issue with 3rd party software.The system dumps duirng the installation of softwares,for example hypersnap apps or video converter,nero etc.[today i tried to install Firefox but the ystem first gets hanged and then dumps]
Previously i had to reformat it 3 or 4 times to get it fixed.
But this time it fails too.
Just today only done the formatting.
But unable to install any third party software. coz the system hangs and then dumps.
currently only my anti-virus,winzip,office word 2010,tera copy are the softwares,am using now.
I have checked my HDD.With CHKDSK utility,it showed no error.
For RAM its working fine.thought have done no such utility test.
So would be grateful to you guys if you can point out the cause of this erratic behavior of my system.

 

[sharkbyte5150]

Got a spare power supply you can throw in there?
Check all connections, especially power to hard drives.

Sounds like you're using a lot of questionable software on your system, but I'd look at the power supply first.

 

[Pranajit]

So far my power supply is concerned,its working absolutely fine.and i forgot to mention that i have already tested it with a spare power supply.
Last time i have changed the RAM slot,so it worked fine for 2 months,now again the same problem