Just to let know the guys like me that official documentation and consultants in computer stores lie :)
They all say that the laptop supports only up to 4GB of RAM as a total maximum (up to 2GB per slot). Anyway this is bullshit.
Also you can find in internet that you laptop is not compatible with SATA II and supports up to 320GB hard-drives. At least consultant will try to make you sure that 750GB hard disk is too large for your laptop and it will not fit it by dimensions, he will say that maximum you can try is 640GB. Well probably I was just lucky to find a compact 750GB hard drive by Seagate that has the same height as my old 160GB hard disk.
Anyway I have successfully upgraded my HP Pavilion tx2500 2GB RAM, 160GB 5200 RPM to 8GB RAM (Corsair PC6400), 750GB (Seagate ST9750420AS 7200 RPM).
I was worried about the warming of large and fast hard drive but it warms not worse than the small did.
Now my laptop works really fast. No hanging up for 10 seconds opening “My computer”. I’m really happy with this upgrade.