Urgent help please (NHATQUANGLAN)

Good day please i need urgent help before my office system will crash.

Many times my system begins to promt and click by itself then it becomes pretty slow and the follow text (C:\WINDOWS\hinhem.scr)appears in the browser, at times too when am working some jargon texts could also apper on or in between my typed document these are what the texts look like( unNgu?i ch?t s?ng l?i freewebtown.com/gaigoitanbinh/index.html
Ngu?i ch?t s?ng l?i freewebtown.com/gaigoitanbinh/index.html)this texts also attached itself to my yahoo messenger sendind transfering files on its own. Some times too the tool bar could click on its own opening the favourites option and several other options. when all this happen it at times highlight documents on its and the keyboard begins to malfuction while the mouse might sieze, I have also notice the folder NHATQUANGLAN when connect external devices like flash,ipods etc to my system and at times they fail to eject. Lastly i cant acess my task manager manager whenever i try ctr, alt and del a box pumps up saying the task manager has been disable by your administrator.

I guess my system is infected and i really need your urgent assistance as this is my office system. my system are:Microsoft windows XP Version 2002, service pack 2
HP Compaq dx 2200mt inter(r) pentium 4 cpu 3.40GHz 2.73GHz,448 of Ram.
if you need any other pls let me know.
I await your urgent response.
Thanks
Judup