More info from http://en.wikipedia.org/wiki/Trim_(computing)
You can see : Windows 7 only supports trim for ordinary (SATA) drives and does not support this command for Storport PCI-Express SSDs that are a different type of device, even if the device itself would accept the command.[39] It is confirmed that with native Microsoft drivers the Trim command works in AHCI and legacy IDE / ATA Mode.[40] Windows 8 and later Windows operating systems support trim for PCI Express SSDs based on NVMe, and the unmap command which is a full analog of the trim command from Serial ATA for devices that use the SCSI driver stack.
So SSD works on winxp but no TRIM, and works on win7 with TRIM, but like alexoiu said the SSD does not get the full performance potential.
* I forgot one thing, your MB has only ICH7 ( not the ICH7R, R means raid support) so you can't use the raid mode either.