Time and Date problem

I use to work on a Windows XP Service Pack 2 system at my Office on which I’m facing clock/time problem since couple of weeks. Whenever I boot my system it shows me Date and Time of somewhere in 2006 though we are in 2007 now. I correct date and time but again at next boot, it changes the time to something randomly. First I thought it could be because of faulty or dead CMOS, so I went to bios checked the time which was showing up correct. I removed CMOS and left the PC turned off for a day. Next day I booted again and still BIOS was showing correct time, so its sure that the problem is not with CMOS, right?

Then where is the problem? Why the time/date gets changed every time on boot up? One more thing I noticed in my time/date properties that there is no "internet time" tab. Any idea what is going wrong with this system?

Please help.

It cannot be the CMOS which held to be responsible for the change in Date /Time on your PC. As far as Internet Time tab is concerned, you should know that if your pc is on any DOMAIN then there will be no Internet Time tab. Anyways, just try out the following steps to fix the problem:

Open a command prompt window (Start | Run | cmd) and enter the following commands:
net stop w32time
w32tm /unregister
w32tm /register
net start w32time

See if it fixes the time problem. Also to determine if the time loss is a result of a weak computer battery:
1. Click Start | Click Run | Type: cmd | Click OK.
2. At the command prompt, type: time /t and then press ENTER.
3. Compare this time with the time that is reported by the clock on the taskbar.
4. Type exit and then press ENTER or click on the Close [X].