- It's free.
- It's very secure. Most linux PCs don't run antivirus software because it's just not needed. You can get antivirus software if you want (also free).
- It's open-source, meaning, among other things, that people can browse the source code. This lets us verify that there is no spyware in the operating system. Microsoft spies on you, as does Apple, as does Google, as does AVG, etc. Not so with Linux.
- Firefox comes with the above mentioned versions of Linux, as does LibreOffice. With LibreOffice, you can open/edit/save Microsoft Office documents in Microsoft format, or in other formats. So, there's no need to buy Word, Excel, etc.
Linux also generally uses less system resources. You could put Linux on the free part of your existing hard drive. You can dual-boot your hard drive and when the computer starts, you'd choose between Linux and XP. The linux installation DVD will partition your drive for you (make a backup first!). If you'd use Linux for nothing but a Monero node, you should be ok with a 40GB partition, but of course more space is better. If you don't have space and can't get another computer, you could just buy a separate hard drive and put linux and Monero on it.
As has been mentioned, Windows XP is not supported by Microsoft anymore. It's not a very secure system to begin with, and with no patches available, it becomes more of a target for hackers with each passing day. It's not a system I'd want my Moneroj on.
As one who's tried thousands of times to explain this to people, but many are stuck in their ways & always having to go back to Windows or Mac because it's the only two options is now the past (Unix/Linux or Open Source Operating Systems have been around for well over a decade). The funny thing is both Ubuntu & Linux Mint are just like a Mac or Windows build, give a Windows user Mint (Cinnamon Edition) & a Mac user Ubuntu (Unity Desktop). It's been over a decade of non-stop people wanting their XP (Vista or 7), even when there's a better soulution out there & the cost of users is far less. I don't dislike Windows, but am not a fan of Mac / Apple & only because of the poverty it takes to utilize. As a kid wanting the fancy shoes, but all grown up & will take the payless brand knowing the cost / labor in said buy.