hi
when i startmy pc it start for kind of 5 sec and then turn off. after maybe a min an a half it start again. time and date are changed (back to 2003)  so i need to change them everytime i start the pc . it now started to restart in the middle of a session ,black screen and then stop of the tower restart and no more problem 
i need help ran antiviruses and changed the batterry no succcess
thank youIs this a laptop?
How old is the laptop?
What operating system?
And, does the battery, if this is a laptop, hold a charge at all? (eg: if you unplug it, does it stay on?)
no it s a desktop about 5 years old windows xp pack 2 the batterry i changed is the one on the mother boardCan you boot OK into Safe Mode?nope i tried that, brought me to a page asking me what did i want to boot first, disk drive or cd rom,i picked disk drive , it WENT on asking me something ELSE which i had no clue about so i safely press esc , it started computer as normal and since it seems problem is gone . could it be so simple ?i have some doubt ...How are you accessing Safe Mode?hitting freneticly f8 at start upIs it Compaq?no philips free line ls1100Its a desktop, so it has a CR02 battery in it... it shouldent be able to recharge. How did you go about recharging it?i didnt recharge it i just changed it as i had a spare mother board at home.
anyway since i tried to start in safe mode problem doesn t accure anymore . strange...If it runs properly in safe mode chances are this is a missing or corrupted driver as Windows only loads minimal drivers in safe mode...
Check Device Manager first for any Yellow !!'s first.

Installed any new hardware lately ? ?device manager is fine no no new hardware since a while .see back to my posts i couldn t run in safe mode . i BELIEVE (but i m no one on computer to have an opinion ) than my cd rom was booting first and that s why the computer was stopping and starting again .i still don t understand why the clock was going back to 2003 ?? but whatever i did it didn t happened again in the last few days , finger crossed .
thanks to everyone for your helping POST and for TRYING with me step by step to find the problem
awsome site !!Nice