Dell is the best option IMHO. Lenovo is very solid too, but of course built in the PRC so one always wonders.
Cinders, get yourself a LaCie rugged external drive and download all your files while your PC is offline. Just let it work away while you're doing other things. You don't want that drive to be contaminated so keep the PC offline when the drive is connected; not 100%, but it will help.
Desktop PCs are almost a dying art around here; lots of powerful units for sale quite cheaply, especially ex-gaming units whose owners are constantly upgrading. Put in a new solid state drive and get the BIOS wiped and upgraded and you're good to go.
I'm running Win7 Pro and when that stops working I'm done with windoze. Good security software is worth paying for.