PC shuts down, struggles to boot, some changes in boot menu ?

Hi Guys Im having problem with my PC. For roughly a week it has seized. Sometimes when Im browsing. It seizes everytime the daughter plays a game on the disney site. It seizes when trying to do online virus scan and when I run AVG spyware program.

The PC will not let me do system restore.

Once the pc has seized I try to reboot and often only get as far as the Windows black screen with the little lights going across. Often it then seizes here. Sometimes it boots to the desktop then immediately freezes, sometimes it turns off in the boot process.

When I do manage to boot I sometimes get a message from zonealarm saying fxnetupdate is trying to access the internet - not sure if this is linked to the problem ?

Occasionally when I check the boot priority in boot menu it has changed to put the floppy as first device. Even whhen I change to hard drive it changes it back within a day.

When booting - Occasionally I get this message " CMOS GPNV CHECKSUM BAD "

Whn the Pc does boot ok I often get this "DATA RECOVERED BY LOG OR BY FILE COPY _ THIS WAS SUCCESSFUL ".


THis problem seems to coincide with the use of a usb memory stick loaned by my neighbour to view his pictures from work. Could he have given me a virus ?


Where should I start to rectify this problem ?

Im running XP on a 3 gig machine with 750 ish RAM. The motherboard I think is ASROCK SIS it says p4s61.

Many thanks - Glenn

 

Could all the symptoms be something so simple ? I will buy a new battery tommorrow and see what happens.