When reinstalling Vista on a 1505, we let Windows Update locate the drivers needed. Afterward, if there are yellow question marks in Device Manager, going straight to the Dell site for the latest in drivers is probably your best bet. We try to avoid using the Resource CD entirely.

My opinion based on experiences past, others may differ.

just install all those drivers against which a tick mark is present

There is a yellow mark on two things:
6TO4 Adapter (Network adapters)
Network Controller (Other devices)

When I try to update the first thing through 'Update Driver Software..." it says that the software is up to date. I read in Microsoft forums that this is a common problem, but not a serious one and Microsoft recognizes it and therefore says you can leave it as it is.

When I try to update the second thing it searches for update long but ultimately doesn't find anything and the error in Properties says: 'The drivers for this device are not installed. (Code 28)'.

Wireless worked fine before reinstallation so I'm kinda frurstrated now and I have a feeling I messed something up :). I went to Dell Drivers & Downloads page and they have 10 drivers in Communication section and 6 drivers in Network section for my model and I don't know which to choose. What's the next step in your opinion?

Thanks for help :).

We solved the issue by downloading the correct driver(s) from Dell.com :)