Laptop Problems

I have a 2 year old HP pavilion laptop. I had to replace the hard drive within a month of owning it and then my CMOS battery died about 6 months ago. I replaced it with a new battery and it started working fine. Then last week it started showing signs of a failed CMOS again (computer crashes, error message on boot-up, incorrect time and date, etc.). Within a few days I had to remove and replace the bad CMOS battery whenever I wanted to turn it on. I ordered a replacement part and before it could arrive my computer crashed for the last time and won’t power up no matter what I did. When I got the new part, I installed it just like I had done tons of times before but, my computer still won’t power up.
I talked to an computer guru when my CMOS battery died the first time, and he thought that I might have a different hardware problem that was causing the CMOS to wear out really fast.
What do you think is causing this?