Random crashing problem (Possibly internet traffic based)

[Chandler_90]

The main machine at work has a habbit of randomly crashing for no real reason.
The setup is as follows -

AMD XP2100+
512MB Ram
20GB HDD

Windows XP sp2

Runs on a 2MB ADSL line using Firefox.

The system simply freezes.. however this only happens when connected to the net and browsing. It also seems to have trouble accessing pages with a large volume of pictures on.. such as a forum.
If you are listening to music or watching a movie then the audio will continue for around a minute after the system stops responding.

Any ideas what could be causing this and any identifiable solutions?

Thanks

 

[uk_viper]

power supply can be related to screen freezes if your PSU cannot supply enough for your conmputer

 

[Chandler_90]

power supply can be related to screen freezes if your PSU cannot supply enough for your conmputer

Right.. I will install a new PSU anyway.
Any other tips?