I'm a classical guitar player who like to purchase a p.c. with good soundcard and not too noisy, for domestic recording.
Is somebody has any advise for me?
You can actually hook up the above equipment to any decent PC you buy and have the flexibility to have a completely dedicated out board recording gear. Lexicon is famous for such equipment and are very highly reputed company.
Make sure that the PC you buy Has at least 4 GB if not more of Ram and a large hard drive to support your storage needs say at least 500GB or better 1TB. You can also consider to get additional storage later for your music files as you progress.
I am in the US but someone will come along and help you with the PC purchase based on prices from UK.
How about letting us know your budget, that will help greatly to pinpoint a system based on your needs.
If you buy any of the Lexicon product your audio needs are well covered and you need not spend huge amounts on a high quality sound card since the out board unit is going to take care of it.