My computer has suddenly started shutting down/rebooting, when it happens I get no error message, no screen of death and on restart I do not get the normal windows has shut down incorrectly do you wont ro boot in safe mode, it is reacting as if i had asked it to restart.

i have run all the anti virus and spyware programmes, nothing found
i have run registry mechanic
i have run bug doctor

i have downlaoded and updated the latest drivers for my mother board and for my graphics card and i have the latest bios installed. My first thought was that it was graphics card related as it shut down during a game, snailmail, but it also shuts down when i am changing progammes, sometimes when it boots back up i can do nothing, icons light but will not act, after normal reboot all work.

i have windows xp, gygabite mother board, geforce 5200 graphics card
500 ram.

Help

Sounds like either the HHD's is corrupt or the CPU is over heating.

After is reboots, enter into the BIOS and check the CPU temp. If its over about 30 - 35*c then your motherboard will shut the PC down automatically to save the board from damage.


Regards
_____
Meck

Go into your system settings for XP and turn off criticl error restart. either Right click on My computer or Click start, Programs, Control Panel then double click system.
Go to advanced and then Startup nad Recovery settings. Under system Failure uncheck the "Automatically Restart" so that you can read the error on the BSOD if you get one.

entered set up at restart cpu temp 57 and rising while idling, got to about 65 set alarm at 70 and got the occasional bleep, gave tht heat sink a good vacuum looks nice and clean and fan running ok. Does this mean cpu is going south??

Nope this means the fan is, as the motherboard will do its best to protect the CPU.
The best thing to do is replace the heatskink and fan. Also make sure the replacement has a good helping of thermal paste and that it is capable of cooling higher clock speed than your current CPU.
If you need more thermal paste, you can get it from Maplin Electronics (http://www.maplin.co.uk/Module.aspx?...dID=4&doy=24m1).


Regards
_____
Meck

I have installed a new fan and the temperature is currently 55-59 degrees c
any other ideas please.

Is it still rebootign/shutdown?

not at the moment