I am download a .iso file and everytime i hashcheck the file its always at 98%. So I let it finish download till 100%. Then I hashcheck again and it’s bak at 98 again. Is there somethign wrong with my computer or bitcomet or the tracker?
Hmm, sounds like a bad torrent. The last pieces dosen’t comply with the HASH.
What you can do is to download the file 100%, and then DON’T let BitComet hashcheck your file. Now try to open it. If it works just fine, then just leave it as it is. 
Also check my signature. Look in the Others section.