Windows XP 32-bit to Windows 7 64-bit

Here:

Newegg.com - Computer Hardware,Hard Drives,Internal Hard Drives,250GB - 320GB

Can I buy new hard drive and install windows 7 on it and unplug my old hard drive without losing data?

Sure.

That is exactly what I would do.

Or you could install the new drive, copy your data to it, and then install Windows 7 on the old drive.

Thanks a lot... :)

Those drives in the link I posted are for a desktop PC.

They won't fit in a laptop. If you need a laptop hard drive, they are quite a bit more expensive.

I have a desktop PC, thanks a lot.

How to check if my hardware components support Windows 7? I have 2 GB of ram, is it enough for 64-bit Windows 7?

I downloaded Windows 7 upgrade advisor and it shows that 2Gb is enough but I've read somewhere that 64-bit Windows 7 will run slow on 2 Gb of ram, that 4Gb is minimum .

Is it true, please help me!

Look here:

Windows 7 Upgrade Advisor - Download - Microsoft Windows

64 bit will run with 2 gigs RAM.

Unless you know you why 64 bit would be advantageous to you, it's probably best to stick with 32 bit. There is no big advantage to 64 bit for most people.

You have a fairly old processor and you may not pass the upgrade advisor test.