Windows 2000 - weird dialogue boxes

[PaulStat]

For some reason in a lot of windows applications the graphics/buttons of the dialogue boxes have become corrupt. See below. Any ideas how to fix this?

 

[Unluckyalf]

Not sure but i think the Powertoy util on the MS website has a rebuild/repair icons function.
Not sure if that will fix your second screenshot though

 

[PaulStat]

looks like that's for winxp not win2000