Windows 7 Time problem

I've been trying to figure out how to fix this problem since I received my computer. It's a custom built computer and has never been able to keep accurate time. Even while I'm using the PC, the clock will lose time. I will set the clock and calendar to the correct time and with in the hour I will have lost 5 or 10 minutes. If I shut my computer off and turn it back on, I will have lost hours if not days. I have made sure that it is syncing, the battery is new (I replaced the motherboard battery a few months ago), I accessed the BIOS and made sure the time was correct there, and I even created a new task that would update the clock every 5 minutes. Now, not only is it still not keeping track of the time, my task scheduler no longer has the task I created and won't let me create any new tasks (forgive me, I can't remember the error that it displays and I am not at my PC at the moment). What are my options? I don't really want to re-install windows 7, although I will if I have to.

Thanks

Try the below solution:
First right-click on the Taskbar clock and select adjust date/time. Then click on the Internet Time tab and select Change settings button. Just then erase the Server field and get it replace with pool.ntp.org. After that click Update now and in a few seconds, Windows clock will get synchronized. Then, click on OK button. Hope it helps.