How do i fix a blue sheen on computer screen?

Not a problem with the graphics card, checked its in its cradle properly and the monitor is tested working fine. Windows XP media centre edition though everything looks blue-ish despite normal functionality of the OS otherwise. Any monitor we hook this up to it comes slightly blue and the colours are distorted. System restore dosent work properly, will re-format help? reeeeeeeeeeeeeeaaaaaaaaaaaaaaaly DONT want to do that though. Should I just buy a new graphics card? thanks :)