can somebody please explain what the (via raid tool) does.
and can i safely remove it.
The Via Raid Tool is a RAID controller for a Via chipset in your motherboard. RAID (Redundant Array of Inexpensive Disks) is a method of taking multiple physical hard drives and making them function as a single logical volume (ie, you can have 2x 250gig hard drives, and the operating system you're using will see them as 1x 500 gig drive.) Raid also allows things like mirroring (where the 2x 250gig drives look like a single 250 gig drive), with any individual piece of data copied, or "mirrored" to both drives. This allows you to have 2 copies of every bit of stored data in case of a drive failure, if you have such critical data. There's also a function called "striping," where data is split evenly across drives to increase performance.
There's a bunch of other odds and ends, with parity and without, and some bits like Striping + Mirroring, and the like.
That's basically a very rough overview of RAID. As a general rule, if you didn't know what RAID is, likely you don't particularly need it. Most likely it can be safely removed, unless your system came preconfigured for RAID, which is a bit unlikely.
I think I can remove raid as I have a 300 gig sata, 300gig normal and a 80 gig normal hard disc drives. I use them individualy for different purposes. but if the tool is not being used is there any point in removing it. like does it slow down booting up.