Pc freezes randomly

[romancandle]

if this is the wrong section please let me know and ill post this in the correct section.my custom built pc will freeze randomly sometimes after watching a couple youtube videos and sometimes after opening/closing a program. i played skyrim for an hour and a half with no trouble but i cant watch youtube? at first i thought it was overclocking that had messed it up so i went back to default settings but it still happens.the only thing i can do when it freezes is to turn it off manually.this is my first custom pc so i may have done something wrong but im pretty sure that all the hardware is compatible.my hardware specs are:

ASUS AMD F2A55-M/CSM Motherboard

Logisys 550W PSU

AMD A6-5400K PSU

x3 2gb Crucial RAM

running Windows 7 Ultimate 64 bit fully updated
all drivers are up to date and working there is no "other" section under device manager and the ram shows up correctly under system properties
i have tried using memtest 86 (one pass) and no errors showed up. any help would be greatly appreciated.

 

[ste_wilko]

What file system are you running? FAT, FAT32 or NTFS?

 

[romancandle]

its on ntfs, i only have one hdd and its fairly old only has 232 gb on it and i cant even boot off of it without setting my sata ports as IDE only just ran a chdsk and no errors where found so i doubt its the hdd at fault

 

[romancandle]

also the keyboard and mouse are still lit up so they are still getting power but nothing responds

 

[romancandle]

anyone have any ideas on this?

 

[romancandle]

i installed firefox and reinstalled flash and it seems to be working now i read somewhere that chromes integrated flash is buggy