Windows 7: HP pavilion frequently hangs up

Hi All

Long time no see guys.
I am helping out a friend of mine with her laptop issues and using my account and teamviewer to post a thread for her.

Anyways my friend has HP pavilion laptop which frequently hangs up for no reasons.The cursor doesn't respond nor does any keypresses.This usually happens on casual browsing or video calls in skype and yesterday it hang up in the middle of teamviewer session.

The specs for my friends laptop is :

HP pavilion
Win 7 Home Premium 32 bit
4 GB RAM
Intel Pentium T4300

The security suit installed is Norton Internet Security 2013 same as mine.

I did check Event Viewer but could'nt pinpoint the problem.

I had suspected overheating but checking on Speccy,the temps are within normal range.

Please help me out guys as to what i should check further and will post Event Viewer logs in next post if that will help.

TIA



Edit: She doesn't have a battery and laptop is always on adaptor

Is windows 7 and all of the laptop's drivers completely updated? The random freezing problem had happened to one of my classmates before but after updating to the latest drivers and latest windows 7 update, the freezing stopped and hasn't happened since.