Re-boot?

[Edward Fitzgerald]

When playing Flight Simulator 2004 the pc will suddenly reboot, this will occurr when I pick an airplane or making other selections. This began after I instslled a Radeon 9600xt. I have the latest driver for this card and have emailed ATI with this problem was told to read the FAQ. which I have done and made changes where applicable. After the pc reboots the error reads "just recovered from a serious error". Also recently while in other programs (non games) I get windows explorer has an error and will close down.
My PC Specs.
Intel Motherboard D865PERL
Intel pentium 4 2.4GHZ proccessor
Bus Speed 800mhz
Memory: 1024 MB Ram
DDR 320
OS: Windows XP version 5.1 service Pack 1 build 2600
Thanks