the battery cld be dead very slight chance of dat cause its new
cld be also due to wrong timezone set it to
GMT+05.30
to do this
right click on the clock->Adjust Date/Time->Time Zone Tab->GMT+05.30
Edit

osted in refernce to Xp
almost the same in Vista(I Suppose)
u can do the same by gng to the control panel ->date and time->Time Zone Tab->GMT+05.30