Bought some new hardware for my secondary PC.
Installed additional 2 TB (a Samsung HD204UI) hard drive and replaced 2x1GB (so 2GB) Kingston RAM with 2x2GB (4GB) Kingston RAM.
Old 2x1GB modules went back to my primary system, from which they were removed about a year ago.

Hard drive is working fine so far. Shows 1.86 TB in Windows.
RAM is a different story. No, the RAM modules are OK, but my 32 bit Windows (Windows 7 to be exact) only shows 3.25GB of RAM instead of 4GB.

Because it would be too much work to reinstall all my stuff on 64 bit OS, I’ve decided to Google for a solution on how make all of my 4 GB RAM usable in 32 bit Windows.
And I have found it. I have found a kernel patch which allows 32 bit Windows to use more than 4 GB RAM.
In fact, even Microsoft themselves have admitted that 32 bit Windows can use more than 4 GB RAM when using PAE (Physical Address Extension) but they artificially limited the maximum amount of memory in 32 bit client systems to 4GB. 32 bit server systems can support up to 128 GB.

I won’t post the patch here. You can find it by googling for “windows pae patch wj32”. Patches are available for Vista and 7.
Be warned that this is a kernel patch. Use with caution.