Computer Freezes Randomly

[Cybernetic]

Hi First my computer is:

Computer: 
   Operating System   Microsoft Windows XP Professional 
   OS Service Pack   Service Pack 2 
   Internet Explorer   7.0.5730.11 
   
  Motherboard: 
  Asus P5LD2 SE
   
  Display: 
   Video Adapter   NVIDIA GeForce 6600 (256 MB) 
   Monitor   AcerView 54eL (9163163) 
   
  Multimedia: 
   Audio Adapter   Creative SB X-Fi [NoDB] 
   
  Storage: 
   Floppy Drive   Floppy disk drive 
   Disk Drive   ST3120827AS 
   Disk Drive   ST3320620A 
   Optical Drive   HL-DT-ST DVD-RAM GSA-H22L 
   Optical Drive   LITE-ON DVD SOHD-16P9S 
   Optical Drive   YA0439M BKB155I SCSI CdRom Device 
   Optical Drive   YA0439M BKB155I SCSI CdRom Device 
   
  Partitions: 
   C: (NTFS)   114463 MB (48603 MB free) 
   D: (NTFS)   305242 MB (305168 MB free) 
   
  Input: 
   Keyboard   HID Keyboard Device 
   Keyboard   HID Keyboard Device 
   Mouse   HID-compliant mouse 
   
  Network:   
   Network Adapter   Alcatel SpeedTouch(tm) USB ADSL RFC1483 (10.0.0.1) 
   Network Adapter   NETGEAR WG311v3 802.11g Wireless PCI Adapter (192.168.0.1) 
   Network Adapter   Realtek RTL8168/8111 PCI-E Gigabit Ethernet NIC 
   
  Peripherals: 
   Printer   Fax Lexmark 4200 Series 
   Printer   Lexmark 4200 Series 
   Printer   Microsoft Office Document Image Writer 
   USB Device   Generic USB Hub 
   USB Device   Lexmark 4200 Series 
   USB Device   Razer Diamondback 
   USB Device   Speed Touch 500 Series 
   USB Device   USB Composite Device 
   USB Device   USB Composite Device 
   USB Device   USB Human Interface Device 
   USB Device   USB Human Interface Device 
   USB Device   USB Human Interface Device 
   USB Device   USB Human Interface Device 
   USB Device   USB Printing Support 

The Problem is while im playing games, surfing the net or even leaving the computer to idle. At random times it just freezes no blue screen of death no nothing so very hard to pin point what could be the problem any suggestions?

[GX1_Man]

Well you put on no information about the make, wattage and age of the power supply.

What happened prior to this? Any recent changes in hardware or software?

The most common causes are heat, bad power supply or defective RAM.