About antivirus. my computer is having a proble with some virus. the problem is when i try to run

Question

my computer is having a proble with some virus. the problem is when i try to run my anti virus , it won't work and quickly minimize. and won't work again.
and when i try to reinstall my anti virus. my computer won't able to install it. as to other software when i try to install, it works. but not the anti virus.

so kindly help me. !!!!!!!!!!!!!!!!!!!

thanking you.
tenzin