I finally managed to get everything work.
Jaclaz was right. The first adapter
was too tall to fit in the notebook, even when the SSD was used without its case. I couldn't find any other, flatter one locally so I order this one
from eBay. It was actually cheaper than the previous one
because the shipping cost was only 1$. It took around 1.5 weaks to get it.
First of all, I can say that everything works properly and there are no problems with stability. The SSD is detected properly in the BIOS and also when installing Windows. As it's a 64 GB capacity drive there are no issues with the BIOS too (its limit is 160 GB).
I took some pictures of the whole 'operation'.
E-IDE cable + previous (tall) adapter + SSD:
As you can see it's impossible to use the SSD 'as it is':
Samsung 470 can be very easily opened:
The Samsung SSD itself is only 1.8' size so it should fit to any laptop designed to work with a 2.5 HDD. I guess it may be important information as the newer model (Samsung 830) is 2.5' so it'll probably not fit when used together with an adapter.
The new flat adapter:
Samsung 470 detected in BIOS:
I did some basic benchmarks. As you can see, performance is heavily affected by the old ATA66 interface and the adapter too:
old IDE drive (Samsung HM160HC):
SSD (Samsung 470 64GB)
The results don't look very promising at the first sight but:
1. Access time difference - 18,2 ms (IDE) vs 0,1 ms (SSD)
2. 4K - huge difference
In general, there's a huge different in speed. You can't even compare system responsiveness on the old IDE drive to the current one. I can say that it's like giving a second life to this old machine
I want to thank everyone for providing help and useful information, and inspiring me to get this idea materialised although it looked quite unreal in the beginning.