Can Windows 7 do software RAID 10 (1+0)

I don't think so. Desktop versions of Windows will only support RAID-0 in software, mainly for applications like editing streaming media. Windows 2003 (and IIRC 2008) will support RAID-1 and RAID-5 in sofware but not RAID-10.

Note that Software RAID support in Windows is generally poor - much poorer than that found in Unix or Linux. You are much better off buying a RAID controller card with Windows; entry level U320 or 4/8 port SAS or SATA RAID cards can be purchased quite cheaply off ebay.

As an aside, I went through this exercise some time ago and wound up going with hardware RAID; this worked well, and there are many, many secondhand RAID controller cards of various specifications available on Ebay. With secondhand cards you are best advised to get a branded one like Adaptec, LSI or 3Ware, and these tend to be reasonably cheaply available. Make sure you get wone wih the right type of interface - Many PC Mobos only have PCI-ex1 slots and most are aimed at 64 bit PCI or PCIe x4/x8 slots.